I'm not seeing why there's so much clamor for them to 'redo' Deadpool. I can understand people not liking the interpretation of the character in Origins: Wolverine, but there are ways to 'redeem' the character without having to toss his use in Origins: Wolverine out the window.
Depending on where the conclusion of DoFP leaves things, I think setting an X-Force film in a variation of the dystopian future that will be featured in that film would be a really neat way to give the franchise its own identity separate from that of the main X- franchise while still keeping them somewhat in continuity with one another.
Alternatively, they could just make the X-Force franchise a completely separate entity from the existing X franchise, which would give them the freedom to 'redo' characters like Psylocke and Deadpool, although taking this approach would mean they wouldn't be able to use characters like Wolverine or Colossus lest they confuse general audiences.