Let me make it clear, 1) I think WSR will replace Wii Sports as the pack-in game for the Wii shortly after it's release.
2) Therefor it will eventually outsell Wii Sports.
Now let's see why this is likely IMO. Wii Sports has Golf, Tennis, Baseball, Bowling, & Boxing. A pair are also in WSR in a superior version: Golf & Bowling. Of the three sports left two have equivalent version on WSR: Table Tennis plays similar to Tennis, Sword Fighting is roughly equivalent to Boxing. (There can't be a MP+ Boxing without a MP+ numchuck) This leaves Baseball as the one sport catagory entirely missing from the WSR lineup that's in Wii Sports & if I were to guess why it's because of the liability of people throwing the remotes into their TV sets. But with the addition of another eight sports it's clear WSR absolutely supersedes the original & almost every new Wii buyer would have that game packed instead given a choice.
So ask yourself, if the number of new Wii buyers are dwindling now what's the point of asking them to pay even more to get what will become the new cutting edge of motion controls. Also, if Nintendo wants it's current users to buy WSR & MP+ wouldn't packing the game into new hardware be part of the greater marketing push. It goes like this: MP+ pack-in = larger MP+ user-base = more MP+ games = more current Wii owners buying WSR!!! = $$$ + a huge lead vs. MS & Sony motion control systems.
Now looking at things antidotally, Nintendo has a history, at least in handhelds, to refresh the hardware every couple of years. Think of Game Boy to Game Boy Pocket, GBA to GBA SP, DS to DS-lite to DSi. So why can't they go from Wii to Wii +? Isn't it especially telling that the Wii Fit's upgrade/sequel is also called Wii Fit plus even though it has nothing to do with MP+?
