If they re-cast him I'd be ok with it. Still I don't think he should be introduced until the third film (if they get that far).
For the second film they should have lost Banshee, Havok, and Mystique.
Possible replacements that they could go with for film 2:
Storm
Colossus
Nightcrawler
Sunfire
Thunderbird (his death would be a cool event, to which Wolverine would be his replacement in film 3)
The important part about using Wolverine is to make him a cool part of the team. Not make a movie that is "Wolverine and the other mutants. Should he be re-cast, I hope they try and go with a more faithful adaptation of the character. I think going that route would really separate this move and him from what has been done to date.