The Borg would be awesome but I'd rather see Q or Trelane. I always thought there should have been a Q TNG film.
I just don't get why so many people are enamored of either the new series or new movies going back and re-treading old ground over and over and over again. Q's story ran full circle in TNG. How many times have we whipped the Borg now? The Romulans? The Klingons? People wanted a reboot- they got a reboot. DO SOMETHING FRESH WITH IT! Wasn't that the whole point? Beyond was a great example of what was possible in terms of a new story. There are more new stories out there. Tell those!
Part of the reason I suggest those other TOS races is because they aren't as fleshed out as the big races from the other shows. It's still star trek, but the reboot allows large creative latitude to reinterpret the aliens as well. Win win Imo.
You know last night I said Azari could be a good Q. Today I thought of a better Q, James Franco. He does kinda look like a young DeLancie.
The only movies to have focused on new aliens races in a prominent way were Insurrection and Nemesis. And you all wonder why Star Trek keeps running back to the Klingons.