There was a time where promote was ridiculously overpowered (and a summoner spell I think?), innervating locket made udyr invincible, Zhonyas ring , giving the good % ap increase and stasis effect, which at one time you could even attack and deal damage to others while in stasis effect. Garen had a 5 second silence and GP could kill his own minions to deny you gold. Wards would take aggro on turrets before champions so you could take a turret with just wards, you know - because you could buy tons of them. The donger had 5 turrets and he could just block an entire lane, nobody could really touch him because he'd jujst stick in his turrets and 5 turrets was way too much, legend even says heimer in beta phase had 6 turrets. Twisted fate had his TP on his E as an ability he could just cast, so he'd tp to a bush (because the range was nearly global) and then he would ward and his team would actually all tp to the bush he was in for the early cheese. Invades early on in the jungle could decide a high level game, first blood gave 500 gold I think.
Dragon and baron were vulnerable to CC for a time, you could pull baron to your base if you wanted as blitz. Poppy had a ridiculously long period of invincibility as long as she ulted the support, she challenged a hero with her ult and only they could damage her. Dodge runes and items existed, there was stackable tenacity sources.
Even later on things like Mad stoning in the jungle was a tactic, which you can look up a trick2g video on it if you wanted.
Oh and trundle with a few items could just walk up to your tower and take it with no minions or anything, just tanking the tower and smashing it until it was dead.
so before you say "rito wtf is your balance team doing, xyz is super op" (which by the way I totally understand) just think about this and be glad you didn't have to be there for it.