I wouldn't mind that look for Beast.
It's funny how much it bugs me to see the characters with different faces now that I'm used to them looking a certain way in the first two movies.
Having Iceman be transparent would be cool, but I imagine that would be kind of expensive and time consuming. They'd probably have to film every scene twice, once with him and once without him (to get pictures of the stuff behind him). I don't know if that's the best way to use there budget.
Maybe they wouldn't be filming the scene twice, but you know, filming him and then filming the actor in front of a blue screen. Unless the character is totally CG. Still, I don't know squat about special effects, maybe it would be cheaper than I'm thinking.