TNG was on air for seven seasons, amassed a big fanbase of its own and was about to go into feature films, surely the series had enough weight behind it to do its first film without a crossover.
By the time Generations came out the torch was well and truly passed I'd say. They should've had the TNG crew standing on their own, without the need for Kirk.
I liked the scenes on the E-B, but they could have related more to the story/mystery that the E-D crew would then come to face. (Which could then have been a nice little lead into a new series based on the E-B