The death of Kirk was a let down, though I now see it as more realistic.
Something I've been thinking about for a while, but I haven't been able to assemble any kind of coherent theory around:
There is an idea, very prevalent among sf fans, that any number of things can be mashed up and produce something where the whole is greater than the sum of its parts. Thing is, for every Blade Runner (film noir v. sf) there's a dozen or more that just don't cut the mustard. My current thought is that any idea can be at least good, if not great, but it requires lots of time to develop, and lots of talent.
In context, Kirk was a classic hero, love it or hate it. TNG was not about classic heroism; it was, as you point out, more of a realistic portrayal. My sense is that the Creators were working on more of a TV schedule, and so instead of taking the time to develop Kirk's role so that he could have a hero's death, they wrote something that would easily fit into a TNG episode (cm/cf Tasha getting killed by a malevolent oil slick, Sarek dying from what amounts to dementia). Kirk deserved better, but he was never going to get it in TNG because Kirk himself was not cut from the same fabric as their people.
Personally, I think of his death as having occurred at the end on the Harriman/Enterprise-B section. That was a heroic moment, and we saw Kirk at his very best. I can feel how much he wanted to take the center seat when it's offered, and he still did the right thing.
I found the plot/Nexus confusing/ill-defined. Still do
So do I.