The only time I get annoyed with WHM dpsing is when their damage interferes with their healing. Like holy for example. If you spam it so much that your MP drops to 400 or less and you're unable to keep us alive because of that... Yeah, then we'd have a problem. I've seen that happen before too.

If you're not running out of MP and keeping people alive though, I don't see an issue. I'm always popping DOTs and such as a SCH, but I guess people generally expect SCH to be doing damage more than a WHM.