[S2 Spoilers] (IMO) Season 2 falls into the same trap that so much of modern storytelling does these days.
Arcane s1 was one of my favourite pieces of entertainment, period. Not just compared to other animated stories but compared to any media as a whole.
The slower build up, the more grounded stakes & world building was something I feel like a lot of us loved.
Then the characters themselves with the way we seen the sisters tragic backstories going into Act 2 & the way they made the main characters feel so alive with all of their struggles & issues was peak TV for me.
But then... season 2 comes along and falls into the same pit that so many stories do in similar genres these days. Almost all of what we loved about S1 takes a back seat to your typical "team up to save the world/stop the big bad" "epic" conclusion.
The problem is that when you commit to that type of ending, absolutely everything takes a back seat to the grand conclusion and most of the best parts of your story are just completely set aside for set piece after set piece & action sequences.
The easiest way I can explain it is we got yet another "Marvel" conclusion which felt very jarring compared to S1.
Reading others comments I feel like a majority of people would have preferred a continuation from S1 in terms of the pacing & characters interactions. Pushing all of that aside to rush to a big war against a supernatural threat takes Arcane from one of the most emotionally provocative shows I've ever seen to just another generic super hero movie.
S2 had these moments from time to time such as Jinx & Vi talking like real people at Victor's commune, but they were so few & far between because the 1000mph plot drowns everything else out.
Tl;Dr sometimes it's better off having a story with smaller stakes & more personal storylines from beginning to end. What made S1 so great was essentially gone by the time we get half way through S2. I hope in the future the stories have a similar tone from beginning to end.