Give Michael Dorn his Captain Worf show. Set it 20 years after Nemesis. Make the ship a long range tactical explorer; a ship with fierce teeth meant to push the boundaries of exploration while at the same time protecting the UFP from threats before they get to close. Get one person from DS9 and one from Voyager. Maybe Tim Russ as Tuvok at Tactical, Aron Eisenberg as Nog in Engineering. Or hell, maybe Naomi Wildman all grown up and in Starfleet. She grew up nicely. Ahem. Give Worf a new character female XO, and fill out the ranks with other new people/young people. Have frequent cameos from other Trek alumni as their characters. Admiral Janeway. Ambassador Picard. Captain Riker and Cmdr. Troi of the Titan. Professor Rej Barclay at the Academy. Captain La Forge of the Challenger. The Doctor. Captain Kira at DS9. So on and so forth.
You can't just toss most of the TNG cast back into their suits and go. I don't think Spiner would do it, I know Stewart wouldn't do it but once and a while to be with his friends. Frakes isn't young enough to carry the center chair. Hollywood BS won't allow you to have two female leads in their 50s like Marina and Gates. Not sure Levar Burton would go back unless you suggested Captain La Forge show, lol.
Dorn wants back in. Tim Russ has been doing fan stuff, so he wants back in. A fair number of the alumni want back in, and will be easy to sign up. Take them, do what you can, fill out the rest with new young eye-candy to draw the kids in. There are only a handful of alumni who don't want such; Shatner, Stewart, Nimoy, Spiner, Beltran. McNeill and Dawson are both behind the scenes now. Siddig and Meaney are doing well career wise. Other than those... you've got your pick.
Basically, it's following the "Dallas" route. Only with a much bigger ensemble to trot in and out now and then, and 3 shows to spin-off rather than one, while keeping TNG at it's core by having Worf as Captain.