The Trial chamber things are going to be the exact same as the Warden in the end. The players will completely ignore the linear layout of them and just strip mine them all away, leaving just the spawners. Then they will use water and stuff to move AFK players around (more players = more efficient and better rewards, like they said) to activate the spawners and then the mobs will drop and be auto killed, then the spawners will shoot out diamonds and emeralds and it will be an AFK diamond farm. Following this Mojang is going to completely gimp it hard after the first snapshot and then in the end the rewards will be meaningless garbage and nobody will ever even touch the Trials at all because there is no reason to do them.
This happened with the Warden, this happened with Raids, this happened with Bastion ruins, this happened to the cave ore gen overhaul, its going to happen again, because Mojang will never learn that adding linear activities to a game that only autistic metaslaves play is never going to end in the way they want.