The problem is that once a hero with aftershock gets enough attack speed to cast arcane orb within the stun duration, there's literally nothing that can be done. This would be fine if they'd just managed to pick abilities with very low cooldowns, but I'd argue it's a bug for arcane orb because it's an attack modifier and not a spell.

I'm pretty sure arcane orb triggers aftershock because in mechanics terms it needs to proc essence aura (vs poison orb/any other orb + aftershock). They can probably code specific exceptions around it for each of the abilities that need adjustment.

Likewise with toggles + aftershock/static field/overload. You should need to pick an actual "spell" to trigger these effects.