Alright so I've been running a nice Mega Gallade squad so I figured I would post my thoughts on it.
Gallade (M) @ Galladite
Ability: Steadfast
EVs: 252 Atk / 4 Def / 252 Spe
Jolly Nature
- Swords Dance
- Close Combat
- Zen Headbutt
- Knock Off
I've actually found Galladite to draw a similar parallel to SD Haxorus. It's kind of annoying to put on teams because it has jack shit for resistances, and your most threatening move, CC, has to be used carefully, as its most valuable asset lies in its bulk. Since you have no recovery, any hint of chip damage, even from U-turn, makes you much more susceptible to revenge killing. On top of that, the pre-Mega is below average for an offensive mon, and post-Mega still leaves Galladite outsped by 115s and above, of which we have plenty in the tier. Even worse is that since you're running Gallade as your mega, you have to rely on defensive answers or Scarfers to handle all of the 135-150 range, as no viable 'mons in the tier naturally outspeed those Megas, and Scarfers can lead to inconsistent results in taking those out since a lot of them carry Protect.
If anybody remembers, Haxorus saw quality tournament play in Grand Slam from players such as NEW BREED alongside Tailwind Whimsicott, as that alleviated its problem of being revenge killed, and both of them have good type synergy together. I decided to try something similar, as Whimsicott's most common answers include Empoleon and Nidoqueen, both of whom eat a clean OHKO from Gallade's STABs. With that Tailwind under its belt, it completely crushes more offensive teams with its excellent STABs and Knock Off coverage to bone those overlapping Psychic-types. Thanks to the boost in its defensive stat, even LO Lucario's ExtremeSpeed falls short of 50%. Inner Focus is kind of niche but in this meta it's definitely valuable as it means you can't just stall out Tailwind with Fake Out Lopunnite, and even outside Tailwind, Scarf Jirachi can't just flinch you down from 100%.
It obviously crushes stall unless they have an extremely niche counter such as Doublade or Spiritomb (RIP Sableye), which are extremely terrible in this metagame because of Lopunnite. By extension, teams that have more of a defensive nature to them really don't like to see Galladite, as it 2HKOs even Aromatisse and PDef Florges at +2, both of whom don't OHKO back.
+2 252 Atk Gallade Zen Headbutt vs. 252 HP / 232+ Def Florges: 291-343 (80.8 - 95.2%) -- 56.3% chance to OHKO after Stealth Rock
+2 252 Atk Gallade Zen Headbutt vs. 252 HP / 252+ Def Aromatisse: 276-325 (67.9 - 80%) -- guaranteed 2HKO after Stealth Rock
0 SpA Aromatisse Moonblast vs. 0 HP / 0 SpD Gallade: 182-216 (65.7 - 77.9%) -- guaranteed 2HKO
0 SpA Florges Moonblast vs. 0 HP / 0 SpD Gallade: 204-240 (73.6 - 86.6%) -- guaranteed 2HKO
I'm still deciding whether or not to ban it, as it did require a decent amount of support to pull off effectively, but altogether, the team is very very strong, and Gallade enables me to give much less care about defensive responses to my team. I'm gonna continue to test with other builds to see if I can get a more informed decision, as Bulk Up with Drain Punch > CC seems like it could be a good win con for balance teams, maybe with Toxic Spikes support or something. Hopefully someone else can post an opinion of that set n_n