While I do support the idea for the Wii, I can't say it is a "reason to buy a Wii" for many people these days. Simply put, GTA has been played out and overdone. After playing Saints Row (not to say it was a bad game), I pretty much realised that I'm sick of this genre. Granted the "sandbox" effect has been good for many games, the whole thing just seems so "blah" these days.
It could move a few more consoles, but I really don't know if it will do anything to improve the opinion of Nintendo overall.