I think they would have lost Patrick Stewart if they would had continued-
They could have gone another 3-4 years with Captain Riker- in retrospect, would 10 years of TNG & no "Voyager ", or " Enterprise " have been better ?
I say yes- the public has more affection for a singular show, than a "franchise"
Are we certain that they would have lost Stewart?
No. The main cast were under contract for season 8; they all signed two year extensions after season 6. And they were ultimately paid both for Generations and the unfilmed season 8. So, we would have had Stewart and Spiner in a hypothetical season 8.
One interesting side effect if there were a season 8 -- the ending of "Second Chances" probably would have gone differently, with Will Riker dying, Data becoming the first officer, and Thomas Riker as the new Operations Officer (or whatever Data's role up front was). The only reason they didn't do that was they didn't want to shake things up knowing that there was a movie on the horizon. Which shows you how long they knew that TNG was ending, since "Second Chances" happened at the end of season 6.
If Paramount hadn't wanted to launch UPN in January 1995, I think we would've had an eighth and final season of TNG, followed by a movie bringing Kirk and Picard together for the 30th-anniversary in the fall of 1996.
It's funny, before you mentioned it I could have sworn that Second Chances was an earlier episode, perhaps of Season 4...
Odd!