If that is the case, then Stannis should have focused on getting the Reachmen to his side first, and flushing out anyone who might disagree, like Loras and Randyll. Then once his hold over the Reach is secure, Stannis can then send the massive Reach army to King's Landing. No amount of Tywin coming to the rescue is going to stop THAT.
If anything, Stannis was foolish to let Loras and Randyll live, since those two could easily lead a counter-attack even if his attack on King's Landing was a success. Sure, he'd get to Joffrey and Cersei and kill them, but with Loras and Randyll nipping at his heels, he'd still get fucked, especially once Tywin showed up.
Then again, Stannis should've pressed on and defeated Loras and Randyll. Push the advantage and remove the Tyrells and Tarlys from the equation, or force them to surrender and submit. Make sure the Florents' plan succeeded, then Stannis can take a massive Reach-Stormlands army out to King's Landing, throw caution to the wind, batter down its walls in a land battle, or attack from the land and sea, with the Reachmen under the Florents attacking the city gates while the Baratheons at sea try to seize the mudgate on the shore. Tyrion can stop one, but not both, and they'd still have enough men to push Tywin back when he inevitably comes to reinforce Joffrey.
This is another one of those oversights which don't really make sense and cast a lot of light on Gurm's lack of strategic expertise. Stannis's army is explicitly said to be composed mostly of Stormlander & Reachman cavalry (his own ragged Narrow Sea forces forming their infantry) and they don't have any reason to feel like they've got to rush to King's Landing, since as far as he knows post-Renly's death, Tywin is still stuck in the Riverlands duking it out with Robb. There really was no reason why he should feel he had to take KL NOW NOW NOW instead of taking his newly-expanded mounted force, chasing down Loras & Tarly (who had fled ahead of the vast majority of their knights defecting to Stannis), and blitzing the confused & crumbling Reach camp at Bitterbridge (where the forces Renly had left behind were mostly infantrymen) before the Tyrells could rally them and purge the Florents.
If he'd buckbroken Mace Tyrell there (easy enough, he's well known as a soft retard, hell if Stannis could capture Loras on the way to Bitterbridge he could probably make Mace bend the knee without a fight even) and doubled or even tripled his own army's size depending on how well the events at Bitterbridge go, then the Mannis could march on KL far more comfortably & securely. By shattering the Tyrells or else making them bend the knee at Bitterbridge, Stannis also wouldn't have to worry about them after he takes KL, the way he would have had he won at the Blackwater. It's such an obviously beneficial strategy that most fanfiction, forum-based roleplays, etc. I've read that deals with Stannis winning the Wo5K usually have him going this route. Wish I could be surprised that random autists online considered this possibility where it had escaped Gurm, but then other such autists have also been able to write scores of endings to the story he still refuses to finish over the years, so...
The one even semi-passable excuse I've seen over the years on this subject was that Stannis felt he had to outsource the task of subverting the Reachmen to his Florent kin, so as to honor them for siding with him & demonstrate his trust in their abilities to win over their countrymen, which they may have hyped up way too hard in front of him. However even this falls flat since the generation of Florents living during the events of ASOIAF are pretty much all obviously incompetent retards and this was known to Stannis himself (Stannis's own Florent brother-in-law Imry was given command over his fleet and proceeded to charge right into Tyrion's trap, Stannis himself even denounces him as a tard for it later). Got to blame this one, among many others, on Gurm and his need for the story to go a certain way I guess.
That made no fucking sense. After the Tyrells and Lannisters reconciled, they should've immediately moved to combine their naval assets to take out Stannis first. Especially since it was Stannis who threatened the capital, not Robb Stark who just wanted to be left alone with the North as a free entity.
As said, Redwyne apparently did not bother mobilizing his fleet until after the Lannisters & Tyrells has reconciled (so as to not make it look like he was mobilizing against either his liege or the people holding his sons hostage), and presumably ordering so many captains & sailors to collect their weapons, leave whatever ports they were chilling at previously & gather at the Arbor's military port(s) would have taken a lot of time. Moving to the Narrow Sea would've taken even more time, considering they'd have to sail from the Arbor around Dorne & the Stormlands first and that since Westeros is supposedly the size of South America, this would be like sailing from let's say Valparaiso to Montevideo - of course, without coal or oil-powered engines and propellers and whatnot, just the wind blowing their sails.
In light of all that and what the story had determined for his role at the outset of hostilities, this one apparent deficiency in strategy, IMO, actually made sense. Stannis also canonically retained the loyalty of most of the former royal fleet (hence why Tyrion's fleet was barely 1/4 the size of his own of 200 ships, even after being reinforced with requisitioned merchant vessels & such) and
Gurm said the Lannisters personally have a fleet of only 20-30 ships at Lannisport, so it's pretty reasonable that Tywin wouldn't have bothered sending those until after Redwyne got on board - even if they could have combined in time (keeping in mind that Lannisport is further away from KL than the Arbor, so it's quite possible that the Lannister fleet wouldn't even have gotten around Dorne before the Battle of the Blackwater happens), they would have faced odds as suicidal as those of Stannis vs. Renly in a straightforward land battle.
He kind of is, because Stannis has been to war before, and he knows what it's like to starve inside a castle, surrounded by a large army feasting at his walls. The only thing stopping that from happening again was the fact that Tywin and the Tyrells had some Northern bugs to squash. So even pre-Blackwater Stannis had eaten a lot of humble pie back during the war against the Mad King.
Yes well, Stannis did prevail over the Tyrells that time too, so while it may have been a harrowing experience for him it didn't seem to have been a humbling one like his actual defeat on the Blackwater. And like the Lancasters, his plan (kill Renly with Melisandre's magic to avoid getting curbstomped by his far superior numbers-->take his now leaderless army-->take KL) was mostly theoretically sound, minus that last step for the reasons elaborated upon above (which as said, I blame on GRRM not being as great and 'realistic' a strategist as his own characters), it just went horribly awry in practice towards the end.
If he had no real plan and was basically dragging his followers into an elaborate form of suicide then I might agree with you, but there's a gulf between that & simply having an actually fairly sound plan which then fails in implementation due to unforeseen circumstances (the wildfire, Lannister-Tyrell alliance, Tywin being able to go straight to KL due to Edmure accidentally blowing up Robb's strategy due to Robb not telling him about it...). We never get to see things from Stannis' POV directly, but at the time, I can see why he'd have thought he actually had a chance at taking the IT even if nearly nobody else around him could've predicted it.
The Starks aren't known for honor. Ned was because he was raised by a man whose words were As High As Honor. He raised Robb and Jon with those ideals, though.
This is true. Most past Stark kings & lords are by reputation actually grim, ruthless and extremely warlike - not particularly honorable types. Their occupation of the Three Sisters (islands between the North and Vale) was so legendarily brutal it was dubbed the
'Rape of the Three Sisters' and forced the Sistermen (who still seethe at the North about it in the present day, 2000 years removed) to become Arryn vassals for protection, for example. They unified the North mostly through war & buckbreaking their regional rivals (of which the Boltons were the foremost, naturally), not through guile like the Lannisters or diplomacy like the Gardeners. Other Starks were famous for
'having the wolf's blood', being very mercurial & hot-tempered characters, like Ned's brother Brandon & sister Lyanna. Wolves are rarely cuddly animals, after all.
Their only rivals in the North are the Boltons, who are seen as creepy due to all the flaying.
honestly, i have low standards in general, but i can overlook/rationalize most shit. but the Boltons never being deus vulted and every time they're on screen doing progressively worse shit is the main thing i just don't fucking get. even vlad tepes doing his "forests" a couple times would be vulted. flaying/wearing people and their further shit is just fucking wonky, and they live by honor-honor good boys, and nearly all the other factions besides the freys are also good boys. freys are jewishy, they're the only ones that matter and you better know it, so you asskiss them. asskissing-mandatory people make sense and are accurate for people, so are people like joffrey for that matter, but unless there's something i'm missing in lore where the boltons singlehandedly saved everyone in the north, i just don't get it. clearly they didn't make vows to not do their shit to any other reg people in the north, and even then, a nation of ned stark-ites living beside the "yeah i hunt down and rape villagers with my dogs" is just kind fucking ""wonky"".
My 'favorite' bit of lore regarding the Boltons & their relations to the Starks was that at one point they rebelled against House Stark when the latter were still kings, and were joined by a cadet branch of the latter called the
Greystarks. For whatever reason, and despite both 1) the Boltons being the ones to start the revolt (House Greystark was mentioned as having joined them, not being the instigators) and 2) the taboo on kinslaying supposedly being one of the worst things you could ever do in Westeros, the Starks extirpated the Greystarks but spared the motherfucking Boltons. Even if they had grown distant in kinship over the centuries, they're still an offshoot related to the main line and it boggles the mind that the King in the North at the time would be so retarded as to subject them to the Reyne-Tarbeck treatment but
not the house (with a long history of & dreary reputation for being psycho backstabbing bastards, no less) which turned them against said main line in the first place. It would be like if Robb survived & bounced back after the Red Wedding, then decided to annihilate House Karstark but let Ramsay live and even inherit the Dreadfort, lmao.
My second 'favorite' piece of lore here is that time the Boltons flayed a Stark king (the half-Wildling grandson of
Brandon the Daughterless) and somehow are still allowed to live long after that. Frankly they're a blatant case of some houses being given plot armor by Gurm, like the Peakes in the Reach who are literally only ever mentioned when they're backstabbing or otherwise fucking over someone else (often their own nominal allies). If we're going to talk 'gritty realism', houses as blatantly & consistently brutal/treacherous as these would have 'realistically' been destroyed and their lands divided between more loyal, trustworthy ones long ago; in the RL Middle Ages niggers who backstabbed everyone around them all the time, such as
Eadric Streona and
John Wenlock (to name just two examples from specifically English medieval history), would typically just get killed because neither friend nor foe could hope to trust them. That this does not happen to the likes of the Boltons is, to be blunt, more unrealistic than LoTR's orcs & trolls.