I gotta figure the Barbarian wouldn't be too likely to be psychologically affected by such a Chaos spell (by the way, this has a bit in common with another WoM Storm spell called Thieving Wind). I mean, the guy is the loincloth poster-child, after all. His reaction would likely be, "Do you feel a draft?", then back to the fray.
Ninny Wizards and pansy Elves with their higher Mind scores should be more suceptible, I think. How about a Hero must roll equal to or higher than his Mind score to resist the shaming effect and break the spell immediately or at the beginning of his turn? It's bad enough for armored Barbarians and Dwarfs to lose their high Defend values anyway. I'd even allow a 6 or even 5 or 6 to nullify the powerful armor-breaking effect (same roll). In the case of a Wizard with a Talisman of Lore, I'd say the spell blows his robes/pants over his head, revealing a thong.
This spell would potentially function as a kind of Super-Rust, where the real damage would be the loss of expensive armor.

(Borin's Armor and the Wizard's Cloak should be Disrobing Blast resistant.) I wouldn't want to be at the game table when a player lost such valuable equipment to a home-brew spell.

That's why the N. Amer. Rust spell was toned down to only affect any one metal sword or helmet (but not Artifacts). At very high Quest levels, stripping armor could work as a level-appropriate coin-draining device, however.