There are lots of quests that can be completed in different ways. The Thieves Guild have a bunch of them. The main quest not so much because here you're supposed to be the good guy anyways.
Sometimes the choice you make will not get you any reward but that's part of being able to make a choice in the first place. If there's one quest where you can't complete any way your character would (not you, your character) then you skip it and move on. Try to do things your character would.
Wanting the game to react to everthing you do is ok if you're playing a linear scripted RPG, not an open world one. That's not only unrealistic expectations, it's also wanting the game to roleplay for you. That's not roleplaying at all.
Sure, you can solve any quest with either a 1H axe OR a 2H axe. And you get a choice of either weightless heavy armor OR weightless light armor (whichever best matches your hair) to do it in. That's, like, practically infinite possibility!
I gave up on pretending that BGS makes RPGs after a couple of the skyrim hype events pre-launch, and now I love it. It's a great open world action adventure with a few light RPG elements they haven't removed yet. And that's exactly what BGS wants to make.
But there is a TES style game that is a good RPG--fallout new vegas. Made by a small company under a tight schedule, and they managed to put in branching quests, npc interaction and depth, and actual consequence into the game.
So yeah, it's possible to make a TES game that is ask RPG, but that's not what BGS wants to do. Incidentally, the role playing elements seem to have turned off a lot of BGS fans. Go figure.
Rough numbers:
FONV: 6 million sold
Skyrim: 12 million
So what's the cost of making an RPG? If BGS wants to get even bigger numbers for TES6, they're going to have to put more features on the chopping block. (Granted, fantasy sells better than sci-fi, and there are other variables, so it's not quite that simple.)