I don't see how spoon feeding the player everything is an improvement myself. It's your character; that's why most developers give the PC generic dialogue, so that you can fill in the blanks with whatever you please.
That's missing the point. I don't recall suggesting spoonfeeding at any point.
What I'm talking about isn't solely the domain of dialogue trees - the ideal solution probably doesn't even lie in that direction. All I'm saying is this:
For myself, the best way I've always had of describing an RPG to others (and this was more applicable way back in the day when 90% of my peers had no concept of what roleplaying game was,) is that you're directing a movie or television show (or just simply telling a story,) where all of the participants get to be the director, casting agent, and star actor. With current-gen RPGs, we now have the technology to cast an "actor" that looks pretty darn close to every player's ideal. And yet, pretty much without exception, this lead actor has all of the acting ability of a piece of chalk. If the PC is never anything more than a blank slate, then that's what you get - all the charm and appeal of a blank chalkboard.
There quite simply has to be to a way to breath some life into the PC. The more detailed and fleshed-out the supporting cast gets, it only serves to illustrate just how lifeless a character the PC really is. Sure, you're never going to be able to code into a game every single possible choice a player might come up with - even in a tabletop game, the ability of the player to suprise the GM is as old as the medium itself, and quite legendary at this point (the GM's curse, quite literally.) But I don't think you have to, either.
Let's take F3 for an example. The main story is, quite literally, about following in your father's footsteps. There's really only so many possible outlooks on that situation, in regards to the character. The PC's relationship with Liam Neeson during his/her time in the Vault is either going to be a good or bad one - you're either going to be searching for you father out of love and concern, academic curiosity, or to confront him about what an awful father he really is. Ditto if you decide to
not search for him. I think, in a meta sense, there's also something to be said for a Vault Dweller coping with the outside world - and again, there's only so many ways you can really approach that, when you get down to it. Sure, there's going to be permutations for each individual player, and I'm
not saying you need to have the game fill in every blank.
But without a doubt, I think that if someone could ever come up with a way to allow the PC to emote some of this personality that we're being forced to work so awfully hard at projecting onto this unmolded block of lifeless clay we call a PC - it can only serve to make for a better game. Dialogue really has nothing to do with it. It was probably a mistake for me to even bring that idea up. Whatever the solution, all I want is something that would allow my character to take on a semblance of life without me having to imagine it all. I don't need a videogame to let me make up my own stories, after all. A game like Mass Effect is probably going to go further in this direction than something by Bethesda (and probably at the expense of "player choice," which I'm actually okay with - I'm not buying Mass Effect to roleplay as a Citadel Guard.) But surely there's room for a Beth game to take some steps in that direction at all - and without limiting player choice, as well. You don't need to get all that specific with it, really, to add some emotion to your character.
And on this subject of "open world sandbox RPGS," maybe we'd be better off without any sort of an overarching Main Quest. If the "point" is to be making up your own character, defining their goals, and dictating the terms of your own adventure - doesn't a Main Quest sort of just get in the way of that? Any Bethesda game is quite long and dense enough with just side quests that it's not like you'd end up with too "short" of a game if you just took out an element that really at some point is going to have to railroad you into a linear series of events.
Maybe this sort of RPG would be better off if it simply reacted to your larger choices (things like whether or not you blow up Megaton, etc.) Certain quests could open up/close/alter as you progress and make changes to the game world, certainly.