Nice idea with Magcargo, and good point about the standard stallbreaker.
I still have trouble with a different stallbreaker though - Facade Fire Blast Trick Softboiled with Toxic Orb. It's like guaranteed to take out one Pokemon on my team. Anything that checks it hates getting Tricked, and "persuading" it to Trick away its Toxic Orb onto a poison Pokemon is risky (its attacks aren't exactly light). Offensive teams can lay down the pressure I suppose but what about defensive ones?