I'm pretty sure I know why this board was changed from "Gameplay & Balance" to "Gameplay"

It's because 99% of this board's members are Bronze and Silvers who praise nearly every new champion as balanced and fun to play against and Riot realized that not a single person here actually knows the slightest thing about game balance. Therefore, someone working for Riot had the amazing idea to take out the word "Balance" so as not to mislead anyone into thinking this is a good place to talk about game balance since no one knows what they're talking about.