by Doomjester
Just off the top of my head, I'd say that (RAW) you're right about only being able to interrupt move actions. A heroic ability isn't a move action, it's a "Heroic Feat" action which may grant some movement.I've wondered the same thing about Jain's Heroic feat. If you could interrupt it with another attack, it would often be advantageous to do so.
At the moment, my heroes have yet to win a game, so allowing them to do these things might not break the rules for us, but I don't think it's strictly allowed by the rules.