I've read the ratings and some of the non-spoiler user reviews before watching the whole season - the benefits of catching up late :)
Many people criticise that Saitama's screentime was badly reduced and that there are way too many time given to a huge number of different heroes of the Heroes Association. Also, another point was that the main character of the season seems to be the "Human Kaiju" Garou, but the whole show was supposed to be about Saitama.
I disagree. This is still Saitama's show, but I like this new approach and storytelling and how it widened the view on the world of OPM. The first season had a few separate incidents only to show the incredible power of Saitama and all the characters were subordinated to this specific goal. Each and everyone we got to know was key to move the story forward - in this regard, I agree that S1 was superior. However, it was pretty one-sided and I don't think that another copy-paste with different monsters would have done the trick for a second time. Thus the writers went to a different road and it is true that Saitama is somewhat of a side-character and we get to know Garou's story, which is pretty well-written btw.
I liked how we were introduced to a lot of different high level heroes, the fighting scenes were spot on most of the time and there are a lot of them, much more action in S2 than it was in S1. Garou's story is deep, the different heroes are funny and interesting enough (for me at least), the returning characters, like Genos or White Fang are still very cool and well, Saitama is still OP. But this is the point after all and Season 2 uses this "final move" of writing very well.
Look, I really adored season 1 when it came out, it was stupid fun from the first second of it to the very last. This season was a bit deeper, more mature in a sense (still funny) and it takes itself just a tad bit more seriously. I don't think this is a problem, but I must say that the entire second season feels as a mid-act before the finale - which will supposed to be season 3 now? In this regard, yes, there are some things left to be desired. Animation is noticably worse than season 1 but then again, I think it was season 1 being absolutely amazing and this one is just OK. It's not bad by any means.
As for the whole season it is still funny, still OPM-ish, extremely action-packed anime which also has its more serious, touching moments. The main difference is that while the first season was built around Saitama and used his pov 90% of the time, this time the POV jumps from one character to another but the point is that we get to know how the existence of Saitama affects people around him and the world he lives in. This influence of Saitama to everyone he ever meets is the essence of this season and to really appreciate his omnipotence we must learn how these people can handle their situations first.
My rating of 9 is for the whole season itself...it is more likely to be 8.5, but who cares.
