I think that Zard-X's situation has improved slightly between ORAS's immediate start and now with some of the things changing. As noted, Scarf Chomp and Terra have been dropping in usage, and despite the mons that give it problems on Stall, they actually have some new problems of their own: Tyrantrum and Serperior, the latter in particular.
SketchUp mentioned 4 mons in particular.
Alomomola, Quagsire, Slowbro and Hippowdon
All of these get demolished by Serperior and don't like switching into Tyrantrum either
252 SpA Life Orb Serperior Leaf Storm vs. 252 HP / 112 SpD Hippowdon: 437-515 (104 - 122.6%) -- guaranteed OHKO
252 SpA Life Orb Serperior Leaf Storm vs. 252 HP / 176 SpD Mega Slowbro: 377-447 (95.6 - 113.4%) -- 75% chance to OHKO
252+ Atk Choice Band Tyrantrum Outrage vs. 252 HP / 144+ Def Hippowdon: 214-253 (50.9 - 60.2%) -- 89.1% chance to 2HKO after Leftovers recovery
252+ Atk Choice Band Tyrantrum Head Smash vs. 252 HP / 80+ Def Mega Slowbro: 198-234 (50.2 - 59.3%) -- guaranteed 2HKO
And in the case of Serperior, it's not like he's dead weight against offense with Base 113 speed and such easy boosting. Zard-X now has some ideal partners to make sure it can break Stall's cores compared to early ORAS. And maybe I'm not playing the right scene, but I've also noticed a bit of a decline in Azumarill usage, another of its prime Offense checks.
So while Zard-X didn't necessarily improve, some of his more problematic opponents are either more pressured or have declined in usage. I'd say if nothing else, he's much more solidly A+ than he was when ORAS began.
As has been noted a few times, Balance has become more common. How does Zard-X fare against or on current Balance Archetypes?