[Kamog]

I believe that the Borg were never really thought out very well...

Neither was the time traveling stuff with First Contact. If the Borg can travel back in time to change history whenever they want, why didn't they do it earlier? Apparently, the Enterprise has exactly the same time traveling capability, but of course the Federation is bound by the prime directive of temporal non-interference (which they disobey every other episode). By the way, the stuff from the other movies and the original series about traveling back in time by using the sling shot effect, flying around the sun really fast, never did make much sense...