It feels like there enough plot seeds left by PIC season 3 that they could do a new TNG novel drawing on some of them. The unseen cyber-attack during BoBW, or a movie-era novel showing Geordi's marriage, one of Picard and Crusher's five affairs, or the encounter with the Hirogen. Maybe even a "Captain Worf" adventure, though I figure the studio would probably want to keep what exactly happened to the Enterprise-E in their pocket for an on-screen project, at least until the 25th century has been definitely put to bed on-screen for a few more years.
Is there room for a 'final adventure' of Captain Picard on the Enterprise-E? Heck, you could do what the comics are doing and fill the empty seats on the bridge with characters from the other shows! Links to Lwoer Decks/Prodigy storylines
Terry Matalas said that the story of Captain Worf on the Enterprise-E might be best left to the books. As you say, it's funny to think there is now a whole gap to take these cahracters in different directions before they all reunite again in Season 3. We have already had a bit of Riker and Troi on the Titan, there is also the story of their retirement to Nepenthe.