Not regarding the last few comments (this is my first post here, so I have to stay as much on topic as possible), I'd have to say the teams I want to come back would be:

Auricom: Non-DLC for us Americans
Van-Uber: German supremacy in speed!
EG.X: I have little doubt this wont stay, but all the same I want it in!
Mirage: I'm doubtful of this mainly because a good portion of the community thought it was pretty ugly; stats keep it as a contender though
Triakis: It has a low fanbase, commonly thought of as a low quality ship, and a lack of love from the developers (little in-game advertising), but the stats tell little of the story, and this ship reigns supreme on Eliminator with a steady feel and a sense of invincibility
Harimau: A more solid Assegai, it seems to have a LOT of potential in Wipeout

Oh, and I think that aliens SHOULD NOT be allowed in Wipeout, due to the fact that the last thing we need is another cheap futuristic racer (looks back to an old and somewhat crappy future racer on PS2 with needleheaded aliens, whose game title I can't remember due to insignifigance)*shivers*.