An idea on how to solve this cycle of annoying metas (assasin, adc, etc)
The game has 3 phases: early, mid and late. And champions have power spikes accordingly.
ATM Adcs dominate the mid and late and this makes the game annoying.
Imho, a fix would be that all champions should be somewhat equally strong late game with full build.
Why? Because this game's audience is 90% soloq players. Why people hate this meta is that if they have a decent early game is all for naught since bot lane for example is having a blast. Same was before with mid or top. The power spikes should be early-mid and mid game, after that if the teams get to a point of almost full builds, the game should feel balanced and this would leave for great team fights where skill really matters, not power spike. And is logical: both teams fought well to reach that point.