Basically, the simpler the game, the more the GM has to actually design and build it themselves since the game didn't do any of that. Then throw in the mentality that's become popular which states the players have more control over the story in some cases than the DM, and you can see why I think they can be quite shit.
Yeah, there's a happy median between rules bloat and rules defecit.
A system should be robust, consistent, and easy to reference.
Some edition of Runequest I ran had 20% difficulty increments as standard for skill checks, depending on if a task was of "average" difficulty, or easy, very easy, or hard, or very hard, and so on and so forth (percentile skill system, roll under) which helped greatly with gauging off-the-cuff skill challenges that I hadn't anticipated.
Mighta been the new one, or Mongquest.
Neither edition is perfect mind.
Mongquest is terribly edited to the extent of basic combat being being broken without errata (hence why the books were so cheap) and the new one is sorta unwieldy, with the fluffy but sorta vague elemental affinities affecting whole swathes of skills, and especially the default chargen options with family history and all that jazz, which are both too specific to dragon pass and the surrounding areas circa just after the Lunar conquest of The Holy Country, and also tedious as fuck.
But then, I've always had to make do with whatever normalfags I could wrangle for a group, and normalfags make everything tedious.
Shit, I remember one time I ran a one-shot (because I couldn't be fucked to run another for them) for two ostensibly well educated men, who were both too lazy to actually add up their skill totals on their character sheets, and just wrote all the bonuses next to one another, even when I told them to add them up as they got them.
So first time one of them tried to do anything requiring a skill check he looked at his character sheet and just went "Derp?", and the game ground to a halt for ten minutes as they both did something they should have done in the pre-game.
I don't DM much any more.
My upstairs neighbor, who's a programmer said "I'll have a go, how hard can it be?"
So I laughed and offered to lend him my core set.
He looked at the thickness and said "Maybe some other time".
I mean, maybe "rules lite" systems are superficially less intimidating to normalfags, which is why there's a trend for them.