I am a little bit concerned about Borg cubes. They would either be way too small to be a threat – they would be only slightly bigger than the Vengeance. Vengeance is so huge and sinister that Borg cubes won't look as ominous now.
Or... They would have to make them even more gigantic. Now that, unlike Carol Marcus' accent, would be a strange consequence of Nero and friends coming to say “hi”, I must say. Not that I would mind, it would be a pleasure seeing Kirk's ship feel like an ant in the hands of an enormous Borg cube that's playing with it, but it would certainly push some wrong continuity buttons.
I guess an easy cop out would be to send multiple cubes. But I liked Borg's invincibility and relentlessness when they were going alone. So oversized cube for me please, hot and no cream.