As for the /shout thing, almost every /shout still /shout for relic RNG. So yes, if the gap is there then the /shout will /shout for it. Even if that become LS only thing, you'd just see elite group able to clear the hardest content in superb efficiency while /shout pt struggle. You either get into the superb group if you want to take the efficiency advantage or struggle with /shout.
If that happens, it affects 90% of the endgame players in this game.
To say it in a better way, whether none mythic DRG is gimp or not doesn't affect me or you, unless you insist to full time DRG without mythic for some reason. But it will affect me and you if you want to make an endgame pt that can clear content efficiently. Me and you would need to spend more time looking for a mythic DRG to do the content.
Back when Rag was OP in legion and legion was the hardest endgame event, finding 5 DD with Rag gave me the biggest headache. Since most other DD jobs such as empy WAR MNK didn't parse as high.
I'd rather just spend 1hr to make the pt and do the hardest event with any DD job and they all perform in highest efficiency, instead of spending 3 days to make a pt and make a Mythic DRG only DD pt for the hardest content.