Ultimate Cap's core conflict is the fact that he's been displaced in time and therefore has nothing left to live for than to lose himself in service to his country, something that never really gets explored in 616 since Cap's been around basically since the classic MU's inception. While he still needs to represent "truth, justice and the American way," the spotlight doesn't need to be on that aspect of his character 24/7 because there's already a forum out there for exploring what it means for one man to typify the ideals of a nation (ie classic Cap).
I LOVE Ultimate Cap. He's way more human a character than the paragon of square jawed American ideals he is over in 616. I also don't see what makes people call him a tool lol.