The canon of Kirk and the Gang would be the “giant albatross.” With that being the case, why even bother with a reboot of an aspect of the Trek universe that has been fleshed out in the original series and several movies? There are so many other stories within the Trek Universe that have little canon and would have provided a fresh, rich field of storytelling - ya know, something entirely new and not something sorta kinda different. Hell, a movie based on the Mirror universe would provide a helluva lot of leeway for writers if not provide a virtually blank slate. The reboot comes off as a cinematic equivalent of Obama comparing himself to Reagan.
Problem is you’ve got 28 seasons of TV show and 10 movies setting up all kinds of races and people and historical elements, accidentally make a reference to the wrong person in the wrong time and the canonheads get their panties in a twist (again Enterprise). Even the mirror universe has a bunch of canon having appeared in 9 episodes spanning 3 shows. All the reboot is doing is snapping off all the other stuff and giving the a clean slate to play with, now they don’t need to worry if they’re not supposed to meet that race yet or have warp too fast. Reboots (and their cousin ret-cons) are pretty common place, and something Trek should have done a LONG time ago. Problem of course is there’s this chunk of the Trek fanbase that’s obsessive on those things to the point of complaining to the stars about buttons changing function, so they always had fear. Which is sad, because originally Trek had no canon, and it worked better that way, http://www.postmodernbarney.com/author/john/ (weird archive, read from bottom up).