That's a good point.Hyper Voice can go through Trevenant's subs or any subs.
252 SpA Pixilate Mega Gardevoir Hyper Voice vs. 252 HP / 252+ SpD Trevenant: 248-294 (66.3 - 78.6%) -- guaranteed 2HKO
4 Atk Trevenant Shadow Claw vs. 252 HP / 0 Def Mega Gardevoir: 236-278 (69.4 - 81.7%) -- guaranteed 2HKO
M-G can come in as it subs and still beat it 1v1.
How does Aegislash stop that? I understand the Scizor, but not the slash.
252 SpA Mega Gardevoir Shadow Ball vs. 252 HP / 4 SpD Aegislash-Shield: 146-174 (45 - 53.7%) -- 2.3% chance to 2HKO after Leftovers recovery
252+ Atk Aegislash-Blade Shadow Sneak vs. 252 HP / 0 Def Mega Gardevoir: 228-270 (67 - 79.4%) -- guaranteed 2HKO
Aegislash can just about switch in on Shadow Ball and still survive a second hit to 2HKO. It's not a good thing for either of them to switch in on each other, but Aegislash has the advantage against most max speed variants.