Instead of a new series, how about a run of stand alone tv movies?
Perhaps a Sulu movie? Something set on a completely different ship during the Dominion War? A movie focusing completely on one of the alien races? Stuff like that?
I think it could work, considering tv has changed so much, and real long running series are becoming quite rare, with a lot of shows being cancelled after one or two seasons. Sometimes that has to do with quality, sometimes with people just loosing interest because they don't want to to invest to much time into getting to know characters over a longer period of time. As hardcore tv-show fans on this forum, WE are willing to commit to that, but the average Joe doesn't. So yeah, I feel that 90 minute tv-movies set in the Trek universe, with each movie about a different group of people, could work.
You're right TV has changed a lot. And the era of TV movies is dead. When is the last time you saw a TV movie in general? SyFy does one big miniseries a year, but beyond that I can't think of any tv movie/miniseries at all. Throw in the added costs for space based sci fi and you'll never get the numbers to work for CBS to produce it.
I had thought a TV mini could have been a good filler in 2007 to celebrate the 40th anniversary with the mixed TNG era cast fans have always wanted, but now that that opportunity is gone, it will either be full series or nothing.