Eh? The plot of Abrams's movie was that an alternate universe was created because of the actions of Spock Prime. How is that 'fubared?"
Not seeing the problem other than "convenient excuse to have Leonard Nimoy in the last two films to get more butts in the seats,"
That's exactly the problem. The same mentality that made them bring Shatner to Generations, the thinking a 'new' movie (or generation) cannot hold its own in the ticket market.
In the JJ's case, an entire alt-universe had to be created in order to allow 80-year old Nimoy in, bringing the awful Nero and his supernova into the plot with it.
But I confess to be torn between these points, I really am a fan of Nimoy and Shatner and liked to see them both in these otherwise 'meh' movies.