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.
A stock borg cube is still noticably larger than the Vengeance.
The problem isn't the size of their ships, its just the 'we are invincible god like and we want to eatz you' concept of the borg is a bit stale and worked on a on-going slow paced TV series rather than a movie.