I think we're done with the old TOS characters, frankly. The 2nd ST movie is coming and I suspect there will be a 3rd, and then that's it. Abrams will be focusing more intently upon Star Wars (*cough*). Actually, I think he'll do a better job than Lucas did with episodes 1,2,&3 (which I didn't care for; very flat directing leaving key actors appearing as cardboard).
I agree with folks here about a TNG reboot. While the Kirk/Spock/McCoy trio is legendary, the Abrams reboot is going to end and most certainly won't be made into a TV series (TV-->Movies, but very rare Movies-->TV works).
Even though TNG was tired by the 7th season, that was mostly because of the characters. We saw them developed enough that there wasn't much more to do... and besides, they were starting to age and ready to move on. I see enormous potential to take the TNG scenario with new characters and incorporate new story themes, many of which can reflect struggles we face today... the Star Trek tradition.