I think your argument for why DD is unhealthy is very poor, it's ridiculous. there are only a few viable dd mons in the meta and those are gyarados, mence, zard x, and maybe you could consider dragonite viable. gyarados is not very fast after a dd, its still outsped by pheromosa. if you dont play stupid, its not hard to beat it, all you need is a bulky mon that can take it on like rotom-wash and beat it down with priority/helmet. mence is pretty fast but has pretty bad bulk and has to set up to be threatening which is easy to prevent with strong attackers like tapu koko and lele, not to mention its weak to rocks. zard x is probably the least threatening, because literally all you need to do is force it to flare blitz against a mon like rocky helmet landorus, which only takes like 61 from a flare blitz and then it gets weakened by helmet + recoil and you can kill it with earthquake, or set up rocks on a predicted switch. not to mention all dd mons (viable) are susceptible to stealth rocks and status, most notably toxic and thunder wave.  in your thread you talked about how a +2 mega gyarados and mega salamence are incredibly hard to deal with because of DD. first of all, if you let a gyarados mega and get to +2 with DD, it is your fault and not dragon dance's fault. tapu fini shuts down mega gyarados with either natures madness or haze or even moonblast/scald burn. mega salamence was not banned solely because of DD. in fact i would even say that it would have still been banned if it didnt have dragon dance due to its ridiculous power (144 bp stab double edge, not to mention flying stab was incredible in ORAS) and immense physical bulk as well as decent typing and access to roost. its not hard to 'force' haze or an unaware mon onto a team, tapu fini and toxapex can both run it viably and it doesnt matter. priority and faster mons also destroy most dd users bar dragonite, which is easy to deal with anyway beacuse of how slow it is. ash greninja's water shuriken, mega scizor/gross' bullet punch, and even scarf pheromosa/terrakion/nihilego etc can take on all of these mons after a +1 DD, and like i mentioned earlier, if they're at +2 its usually your misplay. i dont agree at all when you say dd is 'uncompetitive' because most well built teams almost always prepare themselves for setup mons, and if they dont, its usually the builder's fault. you might say to this 'well we shouldnt have to prepare for such a broken move like dragon dance' yes you absolutely should. its part of the game, and its perfectly counter-able. you mention that moves like shift gear and quiver dance shouldnt be banned because of the porr qualities of the pokemon that use them. that is incredibly incorrect it hurts, volcarona is one of the most threatening and prominent sweepers in the entire metagame, and believe it or not, i have had some success with buginium z venomoth with quiver dance.  shift gear magearna is an incredibly potent sweeper which gets made even better with soul heart + 130 base spA. its the same argument between dd and other setup moves, like I explained above. i hope i changed your mind with these points because i am generally a person that respects other people's opinions, but i cant really get behind this one cuz of how poorly thought out it is. thx dude