[Dark Fallen Angel]

You are only saying that I cited rare things, but Landorus with Earth Power (and Earthquake) and Tornadus' Hurricane are common, and I've cited them. They are neutral attacks perfectly capable of destroying Ferrothorn, even if it invests in Special Defense. Both of them even carry Fighting-type attacks, so Ferrothorn is very limited on options that they use that it can switch into. Also, I never said that those attacks could even 2HKO Ferrothorn, but that these attacks, when not 2HKOing, can at least cripple Ferrothorn so that the next switch-in can finish the job. As Ferrothorn lacks reliable recovery, it will be put on a though position (Leech Seed is not sufficient).