Earlier this evening I was thinking:
Imagine, a toy, that makes your backpedal speed 1.1x your forward/strafe speed. It is available as a very rare drop, about .2%, from fishing. It works in raids.
In mythic raids it increases your backpedal speed to 1.5x your forward/strafe speed.
What else? Raiders have very little to do these days other than zone into raids. Back in Cataclysm some of them had to open water fish for their food. Perhaps all raid food should come from open water fishing? Or they could settle for easily created food that was, eh, 75% of the stats.
How about a very rare mass rez BoE/auctionable world drop with 10 charges?
A very rare BoE/auctionable world drop raid banquet with 200% of the normal raid stats? Or put it on the BMAH? That would be better.
Like I said, raiders have very little to do other than zone into raids and IMO it would be great to add some progression items that increase the complexity and satisfaction associated with competitive raiding.
A permanent flask with 110% of the stats of a regular flask, obtained via ~100 PvP wins, that would also be something to do.