They can't do that it's practically impossible without getting rid of the diversity in what makes champions different. Often when champions suck it's not that they don't do their job well it's that other champs do their job better.
A meta will always be a thing it can't be avoided. Though (idk what elo you are and I don't feel like checking) for a huge majority of the ranked ladder the soloQ meta differs greatly from the pro meta and gets closer to the pro meta the higher up you go. In soloQ you won't find as much effectiveness in 3 tank 2 adc comps as you will in the professional setting because the coordination isn't there. Things that are strong in soloQ right now are also things that are weak in pro play. In soloQ there are way more champions that effectively work without one tricking that champion compared to pro play and in the end you can make it very far without being a meta slave
There is no possible way to achieve perfect balance where picks are only chosen by specific counters and playstyles it'd either remove generalist champions and force everyone to have their own specific thing or make every champion a generalist