I think the dialog could have been more intense(i.e. Gambit/Wolverine, Wolverine/Sabertooth). As for the costumes, the most obvious are Sabertooth and Deadpool, their appearance is their trademark. I can understand if the wanted sabertooth to blend in more with everyone else physically. As for deadpool im quite sure they'll add his costume with darker colors.
I did hear they're toning the movie down, and i don't like that since wolverine is such a dark hostile violent character. He has so much depth he doesn't deserve a lighter tone. And lastly no captain america? come on... nice movie, but not nearly as good as i expected. The x-men series have a strong following and their story is vast, and with less characters it should have alot more depth and substance than the x-men movies i hope. so far we'll see.