Zakk Wylde would be a good Sabretooth (as Danzig, Wolverine). Here Sabretooth looks like Angel the vampire with a bad-nail day. Another Sabretooth issue, is that in X-Men 1, they act as if they didn't knew each other, and the character is radically different (and cooler) in that picture.
Deadpool, ok, looks like a ninja, which is not bad, but, he is not disfigured (as far as i could tell from the trailer), but, I read he will eventually get scarred.
Then, there is kid Storm and a young Cyclops. Again, what the hell are they doing in this film? Also, why the hell is Agent Zero Korean???
My opinion overall, well, there's going to be a lot of action (to cover the fact that the story seems so ridiculous), and with all this characters, it will be messy at best. I'm watching it only because of the sad, yet only Gambit to have appeared on screen at the cinema (other than his name in a computer screen in X-Men 2).
"I'm the best there is at what I do. But what I do best isn't very nice." -Wolverine, Uncanny X-Men #162-
