GEN was kind of disjointed. There were the TNG cast scenes and then there were the Kirk scenes. IIRC Kirk interacted with only one TNG character, Picard. The Kirk/Picard scenes were the only time TOS and TNG intersected in the movie. In a way, the movie had an odd flow to it.
One feels at times like incorporating Kirk into Generations somehow takes away from the TNG-ish-ness of the movie while still leaving Kirk not being a particularly strong contributor to the story. It's a no-win scenario on all counts.
You may be right about that. The TNG cast is rather bland to begin with. You add Shatner/Kirk, who has a flair for the dramatic, to the movie; and the result that you got was GEN.
Oddly enough, Shatner's/Kirk's presence in GEN was the best thing about that movie, at least for me.
And we finally got to see a face off between the two captains of the Enterprise, another good thing about GEN. Imho, Shatner outshined Stewart in their scenes together. Shatner's Kirk came across as charismatic and youthful. Picard looked old and dour in comparison. Even in the fight scenes against Soren, Kirk looked more like the action hero than Picard did.
Kirk did make a difference, but it seemed so underwhelming. It was a barren landscape, no one was around to witness it except Picard. What Kirk did, essentially, went unnoticed and unappreciated. It was as though Kirk's presence was suppose to matter, but it didn't really matter. Then it was back to what really mattered to the writers, Data's cat. The writers didn't do Kirk justice by the ending that they gave him.