Not very sure if that's enough for this one ... But the new version of King's Shield (so with -1 Atk instead of -2 on contact). That should help to deal with this thing with physical mons.
-10 Def and SpD, +10 Atk and SpA, should make it easier to deal with. I think it's a really good addition to the metagame, as it will help handling the broken Fighting Pokémon (Ledellar, Gallade-Mega, Zangoose-Mega, Heracross-Mega).
OK, hear me out.
New moves:Roost,Defog, U-turn, loses Swords Dance
Blaziken loses Speed Boost for Reckless so now it fills the niche of a good physical Fire type, able to be a good nuke with either Bulk Up or Band.
Blaziken-Mega loses Speed Boost for Regenerator, as well as 5 SpA, 35 Atk, and it gets +10 Speed, +15 Def and SpD, for a statline of 80/125/95/125/95/110. Yes, it's another Fighting mega, but this one is more of a bulk fast pivot, similar to Tornadus-Therian. It gets Defog and U-turn that it gets in Gen 7/8 so it can pivot and be a cool hazard removal, able to win against multiple hazard setters (Glimmora, Ferrothorn namely), as well as being able to switch into a lot of offensive stuff such as Weavile.
And of course, Greninja, Aegislash, Sableye-Mega, Blaziken, Blaziken-Mega, and Kangaskhan-Mega are now all unbanned from DLCmons OU!
Mega Kangaskhan: Updated Parental Bond nerf which makes the second hit do 1/4 of the original damage. Fwiw, Mega Kangashkan still hits hard with this nerf since it effectively has a base 165 Atk. Remove Seismic Toss which is the main thing that makes it broken in Singles.
Simple but effective change on Protean. Not sure if it is gonna be enough in practice, but it does solidify more as a revenge killer and a pivot than an oppressive cleaner.
Another simple but effective change. King’s Shield is what pushed it into the edge. It indirectly makes Defiant more threatening against it, though Defiant mons not named Bisharp wouldn’t use their Fighting STAB on it anyways.
Mega Heracross isn’t what I’d call a powerful Fighting-type compared to competiton unless I missed something (Ledellar don’t even need a Mega Stone while the other three do), but I agree with the rest of Fighting-type kept in check by Mega Sableye. 
+ 
Replacing Speed Boost alone would do it, but removing Swords Dance and giving Defog and U-Turn to compensate may help giving it a new identity without relying on that Ability.
Last one with a simple but effective change, and good on BlueRay also removing Siesmic Toss otherwise the Parental Bond nerf won’t be ever not enough.
