Lets accept that Patrick Stewart has chemistry with everyone. Other than that I disagree with you. Kirk seemed strangely manic and bafoonish in the nexus, running around only half listening to the strange bald man in his house. Picard was never fooled by the illusion, but Kirk lived it for 80 years. That makes Kirk seem like an epic moron in comparison.
I think there was a line in the movie that stated that from Kirk's point of view, he had just arrived in the Nexus along with Picard.
I think that line about "great soldiers not dying but fading away" actually explains my feelings on the matter quite well.
We "know" Kirk is probably dead by the time of TNG. Prior to Generations, we are not given any hints as to how his life ended. I always liked to imagine that he did so quietly of old age enjoying his retirement.
Instead, his death was just as empty as Tasha's death, killed by a freak bridge accident, his reward for wanting to help another starfleet captain and "make a difference again".
If you look at it from a realistic point of view, sure you could say that was certainly a possible scenario. However, I go to watch movies to be entertained. And tragic endings are not entertaining. I'm glad I didn't go to the theater to watch that one, but they did force feed it to me if I wanted to buy the 6 TOS movies on DVD (I had to get the full 10 DVD pack with the TNG movie). I watched it once, and out of all the idiotic stuff that happened, this scene was the worst (and then right after, Data finds his cat alive and cries, and this is supposed to "uplift us" again and leave the film in a positive note