1.
$250 is an awesome launch price. A drop to $199 (or god forbid $149) in 2010 would see christmas 2007 type shortages.
2.
I don't really now here, the products the Wii gets its selling model from (iPod, DS, etc.) all got really good boosts from colors but they are handhelds and are a little different. I know I will purchase a Black Wii (especially if the MH3 bundle comes to the US) to replace my launch day wii (give to my sister) but I could be one of the niche markets you are talking about (my money is just as good though)
3 & 4.
I don't think WSR alone is going to skyrocket Wii weekly sales, there will be a noticable boost and WSR along with Wii Fit + and NSMBWii will kill this christmas making the Wii the hot ticket item again this year in video gaming but most (as in >51%) WSR purchases will be to those who already have a Wii so while this will push some people over the edge it might not be as many as you think (5-6 million is my estimate - but it is purely opinion based)
Currently dreaming of: DKC4 or Sonic the Hedgehog 4 (classic 2D platformers) for WiiWare, Smash Bros. for DSi, New Super Mario World for DSi, a Wii remake or true sequel of Final Fantasy Tactics.
One down, hopefully more awesomeness to come.
