Balancing league of legends

I am by no means fully qualified to tell Riot Games how to do their job, despite that I wanted to comment on how everything just has damage in league of legends. Classes for champions lose their identity because of the fact that champions are all packed with % hp true damage and the only way we see champions get more relevance is by increasing damage numbers or lowering cooldowns, which for damage champions works, but what about tanks? Why do tanks get to have 4k hp roughly 150 armor/mr and still one shot my adc? I wanted to address the fact that maybe tanks should have less damage, more tank stats, durability and cc. If they need to clear minions + monsters why not just add a damage amplifier to the ability that is supposed to be used for clearing? Take the recent Sejuani buffs, she was actually i'd say decent as a tank, relatively annoying durable. Now she has more damage and also takes more damage. I think that if Sejuani got buffs not to her overall damage numbers but an amplifier that was scaled towards jungle monsters and lowered the time it take for her to clear camps, she would have just as easily made a return to the meta as a good tank pick who has a good clear speed. That said I'm just a regular player, what do you guys think?