What if the heaven mimic can cast counterspell at will though? It could then return the favor to the wizard, potential causing the infamous counterspell feedback loop.

Would that count as a victory as long as there is always some person there to cast counterspell? I feel that would create a new religion where people become priests and make pilgrimages to this place to take up the holy duty of casting counterspell at the sky for like a week then rotate out.