The one time we were lucky enough to get two eras of Star Trek on the big screen together, but I feel it was all a bit of an anti-climax.
I know Nimoy turned down the chance to appear, due to the role being a trivial cameo at the start.
Well, that and he thought the script was crap and turned down being the director as well.
I think it would have been better if they worked a way for Nimoy and Doohan to be in the film later on in the 23rd century, maybe they could have done a deal where the TNG crew are battling with Soran and goons on the planet, and Spock, Kirk and Scotty use the Ent-D to battle the bird of Prey.
What TNG needed for its first big screen outing was the be a TNG movie. Kirk and the ENT B crap should have been dropped from the story altogether and the focus should have been on Picard's story. If TNG wasn't ready to be on the big screen without help from Kirk and the original crew, then TNG wasn't ready for the big screen at all.