The finale of Star Trek: Picard included an after credit scene with Q (John de Lancie) appearing before Jack Crusher (Ed Speleers) in much the same manner he appeared to taunt Captain Jean-Luc Picard (Patrick Stewart) in the first episode of Star Trek: The Next Generation. It seemed to be the perfect set-up to another show that would bring back not only legacy characters but some of the characters we'd just met aboard the USS Titan before it became the Enterprise.
According to Picard showrunner, Terry Matalas, though, who appeared at a Picard season 3 reunion panel at Trek Talks 3 [via Trekmovie], the ending of Picard wasn't designed to be a setup for a spinoff. Even so, the showrunner acknowledged that's exactly what the finale did.
Matalas said the ending of "Next Generations," the title of the last episode of Picard, was all about passing the torch to The Next Generation. He didn't feel it would have been right to end the series without doing that.
"So that was watching – literally – their children go off on the Enterprise and paying off Seven of Nine’s wonderful arc from Borg to captain of the flagship. That just felt like a proper ending.”"- Terry Matalas
If Star Trek: Legacy, as the potential spinoff show has been dubbed, doesn't get picked up for production, the ending of Picard will have to serve as a final ending of the original Star Trek: The Next Generation crew unless the new Star Trek: Picard movie that is being written will include the entire cast.
However, Matalas added that he didn't think we need to fully say goodbye to any of the characters. He used Spock (Leonard Nimoy) as an example. Nimoy played the character for a long time so it's realistic that, even if Star Trek: Legacy never comes to fruition, we haven't seen the last of these characters.