Most of the boarders complaining about flats do so because they never wax their boards. If you regularly wax with the right stuff you'll be able to fly by skiers on all but the stickiest of spring crud.
And when I say waxing, I mean doing it yourself. Too many shops do really inferior work. If you must use a shop, keep a small structure brush with you. A credit card can be used in a pinch as a scraper. The bane of speed is wax left on the board.
I think the reason moguls suck for snowboarders is because they're traditionally made from skiers carving.
I don't see many boarders who can handle mogul fields without looking miserable. Likewise, when you've got some vertical ice skating going on a double diamond, the skiers usually have a much easier time maintaining control (two edges and all that).
I'll also note that a flat traverse is way more miserable for a boarder, skiers can "skate" along.
All depends on what you want to do any your interests.
Either way, it's a great hobby.