Wesker in RE 5 is totally fine. Im not sure given some of the comments that everybody read the files that was laying around and read all the articles and stuff in the game or if they just clicked skip on it all. It really tied well from everything he did from the start of the franchise all through the games and his master plan at the end which ultimately failed which is why he lost his cool after such the massive build up. I got the vibe from Wesker in the 5th game that he was still the exact same Wesker from the previous games but obviously he was more prominent and couldnt be in the shadows asmuch because this was his game. Where as in the other games he was given reasons to duck away because he was never the end boss. And in RE 5 his final act was the culmination of everything he had done in all prior games.Maybe you guys aren't looking at it the right way. Why would Wesker changes so much? The simple answer is that RE5 Wesker wasn't really Wesker
The way people treat him is that he should be an end boss you can never kill. And nobody should be able to complete the game and finish the end boss because its wesker.