One for All is still a horrible mode because...
First of all: you are forcing players into something they don't want. Maybe it's different in higher elo but in lower there is so much discontent. Like with queues before you introduced role selection or when people get autofilled. Secondly: this mode doesn't bring anything new and interesting. It's not hyperdynamic URF. It's not strategic DND. It's not challenging SG.
If not for Hexakill One for All would be the lamest mode in the game. Even blind pick has more sense.
devour, any champion with a mark mechanic). It also makes you play the champion in unorthodox ways since you, for example, might need physical damage on a champ that's usually built with AD.