You could try m+ exclusive gear like with pvp, but honestly i really dislike that sorta stuff.
But perhaps more relevant: Why should m+ be adapted to raids?
Honestly it seems better the other way around, and raiders already have an entitlement issue from here to Tokyo.
It's the least seen content, unwieldy and is often tediously complex to the point of spawning addons just to deal with its issues.
Just give players loot each kill, or rather: a chance for loot with each kill.
It might help pre-empt EU inquiries into WoW's use of chance/rng in its rewards distribution as well, as often repeated rng rolls boil down to certainty over time.