1. it will make Billions of dollars
2. it will polarize fans like nothing else
As a Sci Fi fan, I understand that one of the most important tenets of any good Sci Fi tale or myth is that it is deeply established in a canon of its histories and facts and backstories. This roots the story in truth (although this truth may not be relative to the truth of reality).
HOWEVER, in this new movie, they (the writers) really messed with some key canon points, not to mention alot of other small details, from set to costume to character. But I am not going to complain about any of it, because I loved every second of the movie. Every. Second.
These stories to help us plumb the depths of ourselves, and canon simply exists to give the story a parameter, so that it doesn't continually escalate to the point of ridiculousness, like a child telling a story. It's a means to an end, not the end.
So, it's my opinion that as long as they maintain the integrity of the story and characters, and maintain the truth of the world in which they exist, that the canon can be altered in such a way without ruining the purity of the story.
----
Now as for this movie, have already said that I loved it. LOVED it. I LOVE prequels. they allow us to newly discover people that we already loved, and remind us afresh why we love them so much in the first place. and YES, this is the crew we know and love, not young replacements with the same names adapting their tics.
Karl Urban is dead-on as Bones. Anton Yelchin may not look like Chekhov, but he is the cutest thing since baby seals were invented, and you forgive him because of that. I don't even know the name of the guy playing Kirk, but he managed to preserve the bravado and swagger of Shatner's portrayal, but wiped away the slimy layer of oil he always oozed in the role. and Zachary Quinto is just...perfect as Spock.
go see it. it's well-balanced writing and action... it is eye-popping effects and epic storying... it is overall exhilarating and joyful.