When I play ME3 I'm going to go in blind and I'm going to make decisions based purely on instinct. I'm going to screw up on some of those decisions and I'm not going to achieve a perfect victory with my main Shepard, but I'll own the consequences of those choices. In the future I may read up on the mechanics and pull off a perfect victory, but I certainly wont be doing that with my first Shepard, that would defeat the purpose of playing the game to me.
As long as the game is fair, I agree.
I don't think that all of the choices in ME2 were fair. At least one choice during the suicide mission had your team lying to you about their capabilities.
I suspect that the "get a good ending" system will be more straightforward this time - just do all the quests & don't be a dick...