Actually now that i've thought about it, the logical answers from all three camps should be thus;
Nintendo fans should want Microsoft out, because Microsoft's the bigger threat, simply because Nintendo absolutely cannot compete with Microsoft on their terms, given that Microsoft is best at what Nintendo's worst at (Appeal to the Fratcore, Online gaming, and Western Third Party support). If the conditions of the industry ever tilted in Microsoft's favor, it would be ruinous for Nintendo.
Microsoft fans, however, should want Sony out, as the PlayStation brand crowds out Microsoft's business rather directly
Sony fans should want Nintendo out, because Nintendo themselves seem to only focus on Sony as a rival, which you can see with the 3DS. Nintendo and Sony also seem to compete most directly for 3rd party exclusives: Monster Hunter Tri and Dragon Quest X are both great examples here, as is the looming threat of Kingdom Hearts Thwii
Monster Hunter: pissing me off since 2010.
