The point is that they didn't have to make a major change to a universe they had no intention of visiting again. It's like your kid trashing your house when they leave for college. Set things up for Nero vs Spock all you like. The big loss is that all of Spocks work on Reunification was just swept aside. Had to reunify with what is no longer there. There were better ways to do it. Unfortunately, it happened in a Big Summer Movie and that means blowing stuff up.
Don't assume i'm trashing the whole movie. I just found the whole Nero/Spock set-up as unsatisfying. Once the movie got to the new universe it worked extraordinarily well for the most part.