I think Larian doesn't care too much about tabletop rules because most people don't care about it. Show me 10 people who want a 5d thing in there and i'll show you 100 who want more hair options kinda thing. And both of those groups probably aren't even the majority of players.
But then again i believe quite strongly their market is Dragon Age's audience and not DND/old-school BG fans (would explain why the game has more mechanics in common with Origins than BG), so as long as they don't provide worse gameplay than Inquisition it's likely most aren't even gonna know it wasn't faithful/could have been better.
This is probably it.
More people care about their virtual dress up doll getting laid, than if the gameplay is good.
My only hope at this point, is that modders can salvage this title.
I'll be playing Kingmaker, or IWD, or BG2, or working on my own setting.