I've only been in July, but the park isn't anything special, a few smaller jumps and maybe 5 rails, but who cares its summer its just sweet to be skiing. And I wasn't that focused on the moguls but I don't think there were any for the public, the bump camps had that area covered, but I could be wrong. I know there is a run open right beside the mogul camps that could have potential have moguls if you did laps in the same spot for a while.
Your best bet is to call whistler and they would know best.