Usually, yes, but in this case, this is a fallacy. If you boycott the Wii U and Smash Bros U, Nintendo will perceive a problem with the game itself (which there may well be, but let's say it ends up striking a perfect balance between Brawl and Melee for the sake of argument) rather than with this stuff.
Community handling and after care are things that don't directly effect sales (as much). The more powerful route is to cause some strong public discourse that could in turn cause a wider group of people to pass on the game.