LostWinds seems to be one of the standout WiiWare titles, judging from the discussion around the site (and in the comments for other WiiWare game reviews). We're glad you like it, and, we assume, so is Frontier Developments, because otherwise they stand to lose a bunch of money.
Their website features a link that allows visitors to "REGISTER FOR ADVANCE INFORMATION on Frontier's forthcoming LostWinds sequel containing amazing new gameplay as Toku and Enril's incredible adventure to save Mistralis continues."
That doesn't really leave much room for misunderstanding, does it? The sequel's on the way. No hinting, no teasers, just "Hey, guys, we're making another one." Having a quickly-announced sequel makes it seem like an episodic title, doesn't it? We guess there isn't really that much difference between an episodic game and a game with really quick sequels.