Hear me out. The training dummies can be set to any boss, mob, etc., with level difficulty. For example; raid dummy could be set to any raid boss organized by xpac and the difficulties are normal, heroic, and Mythic. Each with 1-(#?) difficulty. Same goes for the dungeon dummy except the mythic difficulties would be +#. I have nothing for the basic training dummy. If this is ever done, I ask that they won’t be locked out. Players can day one set these dummies to mythic(+#).
Additionally the dummies will have do the mechanics as best as possible to what they’re setting. I don’t know if have the dummy moving would work or not. Shriek Wing would send out discs and drop blood pools. Sledgefist would send out a DBM warning about his stomp and charge. Please consider groups being able to use the dummy.