Still, the villain's methods and motives leave me wondering. Where was Nero for the 25 years after he destroyed the U.S.S. Kelvin? Shouldn't Starfleet have investigated whatever destroyed their ship? Did Nero completely escape notice all those years, just so he could wait for Spock — and somehow retain his crew for that purpose as well? How did Nero know when old Spock's ship was going to come through the black hole?
I found it unlikely that young Spock would jettison Kirk, rather than throw him in the brig — and even more unlikely that Kirk would happen upon old Spock. Perhaps some unions are fated, no matter the timeline. I was glad to see Leonard Nimoy in more than the cameo role I expected — his role in the plot proved pivotal, which seemed only fitting.
Why the first black hole sent Nero's ship back in time, whereas the second one destroyed his ship? And why did Nero think that destroying Vulcan would save Romulus? His star will still go nova in less than two centuries. And why did Nero feel it necessary to create black holes in planetary cores? The black hole device was demonstrated to be functional in any environment; a local singularity would've proven just as devastating.
Perhaps the mainstream audiences for which this film was intended won't be thinking too deeply about these aspects.