I'm replaying DA2 atm, and while it's not as bad as people make it out to be (it's actually pretty good overall IMO), I've been reminded just how significant the main flaws are.
1. The wave based combat is absolutely fucking retarded. Sometimes it makes sense, and it does happen in Origins a couple times, but in this it's nearly every single battle, even in a tiny house niggers will jump from the ceiling like spiderman. It really just means you can't plan for battles unless you've already done them, and you don't have good spots for your ranged party members to stand, because the reinforcements always spawn encircling you. So the best strategy is usually to just run back across the map, away from the enemy spawn area.
It also makes some battles take fucking ages, which sucks if you need to replay them multiple times (Quentin).
2. The map reuse is just pathetic. It's already set in one area, so they have an excuse to reuse the Kirkwall maps, but again, it's done every single time. There are like 4 dungeon layouts that are reused EVERYWHERE. These aren't even random encounters, these are main quest dungeons. It's a joke.
3. Dialog options are just non existent, and the text tends to not match up with what Hawke actually says. You get something like "Templars are necessary" then Hawke goes on a rant about Total Mage Death and shoves Anders in a locker. The way its done makes it very weird to switch between the different "types", even if it's the only option that fits what you actually want to say. It makes Hawke sound like a bipolar schizo because he does a completely different voice for each option.
4. Not being able to execute Isabella or side with the Qunari. The Arishok is just too based, and Isabella is a ratchet ass ho.
There's also some other issues I've found out about now I'm playing on Nightmare this time:
1. The friendly fire on nightmare is absolutely horrific. The usual stuff applies, don't drop fireballs at your feet and what not. But the issue is that basically every talent that can hit multiple targets will inflict friendly fire. Even things like Mind Blast, Fenris' Spirit Pulse thing, Miasmic Flask, etc. Really limits their use a lot, especially when they aren't even that good to begin with (miasmic flask gets resisted or lasts 3 seconds). Though really the bigger issue is that all the 2H melee talents are AoE with FF. So you basically can never use Mighty Blow or Scythe without careful micro, unless you want your entire party wiped in 1 second flat.
Also Scythe seems to have a lingering AoE. I've used it, animation stops, Fenris runs up to fight a few seconds later, he drops dead instantly. Very annoying.
Apparently there used to be FF from just auto attacks, but it seems like that was removed with one of the patches, thank God.
2. Gear options are shallow it seems. There's not many unique armour sets or weapons, especially compared to Origins, so there's a lot of mix 'n matching random generic pieces until you get the intended class set for the act. Sounds like it will make replaying pretty lame.
Honestly you should probably just play on Hard if you want to actually be able to use abilities and have fun.
Apart from that it's pretty fun. I don't think the story is that bad, even if you are railroaded a lot (doesn't even make sense to hate mages because of your family background). The combat is quite rewarding and still takes strategy and proper character builds to win on higher difficulties. The talents are quite nice and the cross-class combo stuff is an interesting idea, though its kind of half-baked and not really necessary.
I think my favorite part of the game is when that Hunger Rock Wraith in the deep roads tries to make a deal with you, and if you refuse, Hawke just punches it in the face for no reason.
That or Anders writing a reddit manifesto of arguments about why mages are le good and you can call him a retard.
Or Merril