When Snipers are meta, you get killed from range by completely undodgable autoattacks. There’s little you can do about it. They kite backwards and you’ve lost half your health by the time you’re even on them, and you’re dead by the time you’ve scratched them.
When Mages are meta, you get outranged and CCed —> Blown up by their A and B. There’s little you can do about it. You get CCed eventually and fall over and die.
When Tanks are meta, you get run over by several unkillable monsters who throw their base damage onto you and can duel you despite not building any real damage. There’s not much you can do about it. You pop your CC, they don’t die and they steamroll you.
However, during a bruiser meta, although it may be toxic, there’s more room to counter bruisers because of their inherit weaknesses. They aren’t fully tanky and are taking a risk when dealing damage, they can be outplayed with teamwork and they mostly fall off late game. The toxicity would still exist because SPLITPUSHING, but this is actually somewhat possible to remedy through number changes to the turrets.
Assassin metas (group screech), although even more toxic, has greater counterplay. Assassins are squishy and if you can lock them down (Yes, you can lock Anka down. Pick Cath, it’s pretty great). An assassin meta would likely offer the greatest diversity in character choices and would also be the most dynamic meta possible.
Problem is t4-9 soloQers don’t like getting one shot.
Anyway that’s my TED talk give thoughts below.