Suggestion mainly for the Blackrock realm, but I think it’s a universal solution.
A simple solution would be an option to hide your character's location in friend list after entering a command. After entering command or talk to npc, players could enable a setting that locks their status on the friends list, making it always appear as if they are in Dalaran.
Currently, being able to track players’ locations allows others to dodge queues or snipe teams, which negatively impacts fair competition.
This could refresh the PvP on the server, increase the chances for more exotic comps than warpala, and shift the focus back to true competition rather than opportunistic behavior and queue manipulation.