PBE is NOT a place to balance things
I'm getting tired of people saying "omg riot no listen to PBE players. x so op. y so underpowered" Riot doesn't balance a lot of things around PBE. Why? because there are people from all over the world, with different connection speeds (ping) and their mains having different MMR. Meaning Diamond players get matched with silvers sometimes.
This is also why so much changes went true. Live servers are where they do the balancing and since it's pre-season there are so many changes that ofcourse some of them will be broken (100% crit warlord Yasuo)