I never played FC Napoleon so I can't comment.
This seems to be an accurate assessment of the four FC games:
https://boardgamegeek.com/article/22227540#22227540
Most complaints with Nimitz seems to be related with The Japanese AI randomness vs historical accuracy.
For me that's not an issue, and in fact being a 100% solo player, I welcome randomness.
Check the review below. The author praises a lot FC Napoleon and not so much FC Nimitz.
https://theboardgaminglife.com/2015/04/ ... fe-review/
Anyway, I've only played Nimitz once, but sooner or later it will come back to my playing table.