The weekly quests make me feel forced into certain builds and I stop playing to win.
Each week when I go to play TFT and I see "Play this many of this class/origin" that part of my brain that likes progression and completion-ism forces me to only use that as my build in every match until the quest is complete. Between other people building it and the rng of the store this puts me in a very poor position to have any chance at actually being competitive. Having weekly quests is good, but it would be better if "build this in particular" wasn't one of them.