Sure thing that toppling regimes from outside rarely works and recent events have shown us that. Though the IRGC has a tremendous amount of military power, the civilian population have nothing and would take an immense amount military hardware from the outside with challenging logistics and a massive IRGC fraction and would result in possibly one of the worst civil conflicts in recent history. War sucks, civil wars are worse due to the lack of wherewithal of trust. The cleanest method is probably for the West to knock out the regime and step out of the way afterwards.