What they really need is something to get them past the draught that typically sets in around the summer months, last year they had Galaxy 2 which didn't hurt at any rate. I also think they ought to consider cutting the price this spring, perhaps combine it with some nice bundles. A 150$ NSMBWii and Mario Kart bundle would be awesome! As far as marketing goes, they really cannot assume that word of mouth will carry them forwards any longer, make some good commercials, there is no shame in promoting your products properly.
If they choose to hold off on everything until fall/winter, which is a very real possibility, we could see some truly low numbers (sub 100k is damn near certain) and might send the calendar year sales below even that of the PS3 and 360 even if it were to take the holidays again this year (which I think it won't without some real measures). With a price cut, good support in the form of 1st party titles and decent marketing, it will win the holidays with a slight margin imo, without these, it could be a tough sell (literally).
PS: I'm not taking anything away from the stellar sales of certain games on the Wii, having several 20 million sellers is something Sony and MS can only have wet dreams about but I do find it somewhat worrying that it manages to move less total software when the installed base is that much bigger and I'm sure a lot of developers feel the same way. Also, thanks for answering properly and taking your time with your posts, that's one of the main reasons why I've always enjoyed your posts. There are those who would simply call me a retard and call it a day... 
