Nerf Scald and nerf Knock Off. Neither moves have good switch-ins, outside of Storm Drain / Water Absorb and physically defensive megas, respectively.
Scald's 30% chance is ridiculous. The first part of the equation though is that it's a highly spammable water type move so fire-types that would normally not be affected by the burn aspect have to worry about, well, super effective damage. Water types that resist, too, have to worry about the relatively high burn chance. Getting a burn off on anything is good, except maybe AV Conkeldurr. If Scald's burn chance was lowered, we'd see people choosing between Surf and Scald more. I think that sort of opportunity cost measurement is healthy for the metagame.
Knock Off buff was a horrible idea. I still honestly would rather see the metagame without it. The fact that Dark now has so few resistances means it just utterly maims whatever comes in, unless it's something like, uh...well, nothing really. M-Aggron is probably the best KO sponge, but that's beating around the fact that nothing appreciates losing its item. Knock Off doesn't require thought. It doesn't require thinking about the better coverage move or even switching out. You just click Knock Off and something either takes a wallop of damage or loses its item. Zero thought required.
Along those lines, I think Ghost and Dark need to be re-nerfed in some way. Dark, not as much, at least when we finally get physically defensive fairies worth a damn. Ghost, however, is the new Dragon. Highly spammable, one resist, and one immunity (Normal, which is an awful typing), and it gets perfect coverage with four other types (Dark, Normal, Fairy, Fighting). To be honest, I'm not sure how I'd nerf it exactly because nerfing Ghost means buffing Aegislash (an awful paradox, I know).
Imo we should just set Pokemon ten years back, so no DPP, no BW and no XY. GSC and ADV were better. No instakill buttons, no 100% hazards meta, no ♥♥♥♥♥♥♥♥ hyperoffense ♥♥♥♥ where you win the game by making one doubleswitch and then you just kill, sac, kill, sac, kill, sac.
Nerf offense pretty much. And give non Chansey/Skarm/MVenu/Quag/Glisc/Tran stall teams a chance. XY is so one-dimentional atm, it's not even fun playing.
Hyperbole much? I won't lie that Deo-D/Deo-S makes HO the prominent playstyle, but stall is very much a viable playstyle. I'm an avid stall player, so I know what I'm saying when the playstyle is very much still alive. (Baton Pass is god-awful for it though and Neo-BP is even worse).
DPP was one of the balanced and fun metas so I'm not sure if you were actually around for it, but you'd be nostalgic for it right now. DPP UU is probably the greatest metagame of all time, no lie.
I don't think anyone except me and you want to go back to the stall days of GSC though.