Since I've only re-read the stuff he published from 1939-1950 so far, this is all based on recollections except for
Pebble in the Sky. However, my re-reading experience hasn't been too surprising so far, so I'd think my old opinions would still mostly hold, allowing for some "re-thinking" without yet re-reading. I don't think there's any novel solely credited to Asimov I didn't enjoy to some extent, though
Fantastic Voyage is fairly weak and, if I recall,
Fantastic Voyage II is better in ways but is still a "Fantastic Voyage" and so not really necessary. I agree with the notion that there's Early (or Early/Middle) Asimov and Late, and that Late isn't as necessary, but I always stick up for
Foundation's Edge and
Robots of Dawn. (Really curious about re-reading those to see if that holds.)
Robots and Empire is clever but, even back when, I felt the climax, even for me and Asimov, was too talky.
Foundation and Earth is interesting and has a wonderful moment in it but it's also a disappointing last (in the internal chronology) novel. I won't be surprised if I have even more trouble with this on the re-read. The prequels are also enjoyable but I'm not a fan of prequels. While not as good as
Edge and
Dawn,
Nemesis is a good (and rare) stand-alone, though the least of the three stand-alones and brings up the notion of collaboration. I have wondered if Janet helped any beginning with
Nemesis but I don't know there. His style changed with the 80s novels due to time and the requirement to write longer books but, if I recall, there's some flavor of a further change in
Nemesis.) As far as the credited collaborations, the Norby books "with" Janet Asimov are for small children and are likely just as much by her as the Silverberg novelizations of some stories are by him (which is "entirely") and I don't like what little I've read of either group. The Silverbergs are good enough, technically, I suppose, but there's no point to them.
Basically, I think Asimov's Late phase was much better than Heinlein's but, yeah, the only novels most readers
gotta read are the early novels and
The Gods Themselves. It's just that I wouldn't want to do without them, especially
Edge and
Dawn.
That thread you point to is pretty wild: I said "I've been itching to go on a massive Asimov re-reading binge for years now" and it's been six years since
then. But, finally, the notion of the Centennial just let me throw the Pile under the bus and get to it. While I probably noticed more issues and have stronger philosophical reservations, I still absolutely love
The Foundation Trilogy and think it's one of the greatest things ever. I'm so glad I re-read it.