Influence system should not restrict the player to be a yes-man, but there're gotta be consequences. Both for ageeing and disagreeing. Sometimes agreeing should have negative consequences, just as disageeing should pay off down the road. I think Obsidian had the right idea with AP. There were story benefits to both negative and positive reputations with people. I hope PoE adapts a similar system.
I agree quite muchly.
For example, I'd honestly love to see a situation in which you agree with someone on some heated subject, even though that approach/decision ends up being a pretty terrible one. Then, having that companion find out you were actually thinking of some risks, etc, and say "OMG! You knew this might've ended badly, but you just didn't want to start a confrontation?! You should've told me the truth! My ego would've healed!"
You usually don't see that kind of thing. It's usually just "oh, well, this all went to shyte, but I'm still super glad you sided with me, even in the midst of these horrible, horrible consequences! 8D!"
It's as if companions are just comparing dating profile answers or something, and all they care about is the compatibility percentage at the end. "Whoa whoa whoa... you think we should probably actually find thiscreature's weakness BEFORE we confront it? Well, when we get there, I'm going to realize that's an excellent idea, but I'm STILL going to hate you because our opinions, in fore-sight, didn't align. u_u"