I got into a big argument on the Trek XI board a few weeks ago about whether or not it was a good idea for multiple Trek continuities to exist (since that's what a lot of folks are saying the new movie amounts to -- a new Star Trek continuity). And a lot of folks are strongly against the very idea of a new Trek continuity, even though they have no problem with it with other franchises.
These are folks who want Star Trek to constitute a single, completely self-consistent fictional continuity. Period. They can accept multiple versions of the Batman story, or the King Arthur legend, or what-have-you. But for Trek, there, to borrow another franchise's catchphrase, can be only one.