I really hope M-Gallade stays UU (which it probably won't)
Gallade will probably be overwhelming. It's very fast for this meta, and a handful of mons that can outspeed such as Azelf, Raikou and Alakazam are not able to check it due to its solid special defense. Crobat, Absol and Aerodactyl are definitely good checks to offensive M-Gallade, as are any physically offensive scarf user too, but they're just that, checks. A lot of traditional scarf users, and all of those checks have a death wish if they are trying to switch in.
It's typing and movepool seem to fit fairly well against the tier's defensive mons. Close Combat / Zen Headbutt / Knock Off / Swords Dance hit everything quite nicely with STAB, Knock Off hits super effectively the Psychic types that otherwise wall it. This is an important distinction with "total neutral coverage" as hitting a wall with UnSTAB neutral attacks is useless. Granbull, Florges, Aromatisse being subjected to Zen Headbutt will be difficult, Celebi, Jirachi, and Cress vs Knock Off is not a sure victory for Gallade but a bit prior damage through momentum and hazards is all it takes. Alomomola and Suicune are challenges, naturally, but can either of them do anything but rely on a scald burn while Gallade just continues to Swords Dance right next to them?
and again 110 speed makes it very competent vs. a lot of offense, so Gallade is very flexible on teams creating no new weaknesses for teams against offense or defense and its strong as shit.
for your consideration:
+2 252 Atk Gallade Knock Off (97.5 BP) vs. 252 HP / 252+ Def Cresselia: 320-378 (72 - 85.1%) -- guaranteed 2HKO after Leftovers recovery
+2 252 Atk Gallade Knock Off (97.5 BP) vs. 252 HP / 252+ Def Celebi: 364-430 (90 - 106.4%) -- 43.8% chance to OHKO
+2 252 Atk Gallade Zen Headbutt vs. 252 HP / 252+ Def Aromatisse: 276-325 (67.9 - 80%) -- guaranteed 2HKO
0 SpA Aromatisse Moonblast vs. 4 HP / 0 SpD Gallade: 182-216 (65.4 - 77.6%) -- guaranteed 2HKO
+1 252 Atk Gallade Zen Headbutt vs. 252 HP / 232+ Def Granbull: 207-244 (53.9 - 63.5%) -- guaranteed 2HKO after Leftovers recovery
+4 252 Atk Gallade Close Combat vs. 252 HP / 252+ Def Suicune: 459-541 (113.6 - 133.9%) -- guaranteed OHKO
4 SpA Suicune Scald vs. 4 HP / 0 SpD Gallade: 70-84 (25.1 - 30.2%) -- guaranteed 4HKO
hell: +2 252 Atk Gallade Close Combat vs. 252 HP / 252+ Def Suicune: 306-361 (75.7 - 89.3%) -- 18.8% chance to OHKO after Stealth Rock
not bad at all. Granbull has no recovery, so its generally one of the easier walls to wear down. Cressy needs to go fully defensive and must run Thunder Wave to stop Gallade. A mixed defensive set struggles vs +2 Knock Off and Stealth Rock. This bears a lot of predictability and weakness to special pounding from team mates.
sableye destroys Gallade though, lol