Therin of Andor wrote:
You could get rid of just about any of the TNG characters and it would not be that big of a deal.
Patrick, Brent, their agents and Paramount disagree with you.
"Generations" without the participation of Picard and/or Data
would not have been tenable. Those actors' fan mail piles outnumbered everyone else's.
I've watched many studios and sports teams make huge mistakes over the years because someone is "popular". I'm sure that Shatner and Nimoy both had far larger mail piles than Stewart and Spiner when TNG started. TNG was the proof that Trek was bigger than any single actor. I'm not sure it would've hurt the film series for Stewart and Spiner to have departed as movie Picard and Data bore little resemblance to their TV counterparts. With Star Trek it's always come down to the quality of the writing.
Star Trek became far too conservative under Bermans watch. Only making changes when they were absolutely forced to change. Creatively, live-action Star Trek went bankrupt (only DS9 attempted to break the mold but far too often fell back into Trek cliches).
As in all things, YMMV.