I find it difficult to believe that so many people know exactly who they are going to main. Especially those who try to find ways around the fact certain characters are clearly not as good as others as far as what we have seen, which is all we can go off of. Yes, what was seen was a demo, but we have no idea what will be changed from the demo to the actual game. So the argument that "he MIGHT get fixed" is just as valid as "he might NOT get fixed."
I am not saying that tiers are greater than skill, but when you can not only pick up and play, but master another character that you still like with much more ease, I doubt you will continue to main the former due to the extra effort. You might use said character as a secondary, but I doubt you would actually main him. You [plural, to the group] might still main said character, I just doubt it.
Now for a more optimistic point, I am not an Ike hater. I am not saying that Ike sucks in general, only that he did not play as well as the other characters. I love Fire Emblem and Ike will probably be the first character I try out in Brawl, and I would love to main him. But I am willing to admit he has issues via the demo that may or may not be solved before the game's release. I am hoping they fix the speed issues, especially since the super armor, among other things, was also buggy. If he is not fixed, I will see that for myself and use him on occasion, but main someone else.
~Realism.