I'm only 4 months into League, & already understand people's complaints...
EVERYONE'S talking about there's too much true damage, too much damage overall, tower's are squishy, little to no counter-play to some characters, ADC's receiving a punishment that was too harsh, supports being unable to save the nerfed ADC's, jungle changes didn't work for the best, Baron is too weak, Rift herald hits towers too hard, domination / assassin classes running wild one-shotting everything, games are too short, snowball is out of control, developers wont listen to a thing, and just unnecessary changes overall... the list goes on and on.
I've witnessed if not all, most of these changes in only 4 months of playing. Honestly, It's actually pretty insane.
I do like league a lot, and i'm so new to the game - my opinion probably shouldn't matter compared to those who've been playing since like season 2.. But these changes are really affecting the game way too much - and unfortunately according to most players - not for the better.
I do hope something can be done about it!