Just finished it. I thought I was ready for the end, turns out I wasn't.
I'm seeing a lot of negative sentiment but I thought the final act was fantastic, just like the rest of season 2. Sure, this season was generally messier than the first. There were some jarring jumps and some character motivations suffered from the breakneck pacing a little, but these are only minor complaints for me personally. I guess you could say it was more a season of highs and lows compared to the first, but the highs were so exceptional that I'm fine with that.
Would I have liked another season to space it out a bit more and give certain characters, relationships and narrative beats a bit more time to breathe? Absolutely. However, with how insanely expensive it is to produce, that was probably never realistic. I'm just happy we got a second season at all.
Anyway, sad it's over. I love these characters - I don't think any show has ever managed to get me this invested. Jinx, Vi, Caitlyn and Jayce are top tier but so many others had their time to shine as well. It'll take some time to digest it all, but I'm definitely rewatching the whole thing from the beginning again at some point.