Riot makes too many changes
They've even stated recently that they understand people would learn to cope and counter unbalance if given enough time. But they never give enough time. Instead, they shovel out balance changes like we'd all stop playing if they gave us a little room to get used to the state of the game and play against it.
Hence, we get changes like an armor penetration meta because they didn't give time for people to adjust to the amount of penetration there already was.
The next class update is going to do the same thing that every other class update has done. The changes will make that class and its items the best option for a while. If they'd leave things alone, or release an update on all classes at once, then we wouldn't see this continuously changing meta of un-fun.
The continuously changing nature has been this game's selling point, but it's also the reason it's never balanced.
