First we didn't see either Inosuke or Zenitsu, everything with them gets more fun, but I understand and don't think it's such a big problem.
I feel that the fight with both Upper Moons could have been a little longer. Upper Moon 5 was very disappointing, I know Tokito is a stronger Hashira than Uzui but still... to defeat Upper Moon 6, Uzui along with the other hunters took the whole season, it was a bloody battle that ended with the whole city destroyed, and in this season's battle... well I don't want to give too many spoilers but that's it.
I also thought that Mitsuri should get a little more Screen Time, she basically only appeared for real in episode 10.
Even though the entire review was criticizing this season, it was nowhere near bad. Ufotable doing as always a great job and the last episode was perfect too.
In short, it's a good season, for those who have seen the last two I recommend watching this one as well, although I think the second season was superior in everything.
