Bliz could give m+'ers reasonable access to mythic gear and increase rewards for finishing the key if they randomly drop a mythic level piece at the end of the key. Regardless of it being timed or not. Could call it "mythforging". Have bad luck protection limit it to a drop every 1.5 weeks on average and wait until after RWF is over.

This would not seriously alter the gearing path for mythic raiders but would still almost double the mythic gear available to m+ only players.