But look at Game of Thrones that has gone down that route.
It's on cable, though. On network you need sponsors, which makes half the number of episodes problematic.
The why not go the cable route?
But at the end of the day I would rather see quality over quantity which TNG, ENT and especialy Voyager seemed to go for.
Even DS9 would have been better in series 6 and 7 if they had cut out the stupid holodeck filler crap and SOME of the stand alones and just done 12 1 hour episodes on the war useing the money saved to make them even better