I can only speculate, but the obvious reason a WiiU owner will downplay this game is because it's not coming to WiiU.
XBone gamers, I believe, downplay it because it could very well be the "next big thing" (you know, with the rave previews and the $500M ad budget) and that push is gonna be for PS4. At least, a lot more so for PS4 than for XBone. So they start saying "it isn't that great" to try and undermine and ignore the game, because Destiny will probably be "just another game" for XBone, while it'll be a "killer app" for PS4. If the game had been exclusive to PS4, you'd get the typical downplaying, but acceptance from the previews and people's beta experience. But because they're getting the game too, and it's looking like it's not gonna do much in favor of XBone, they're opinion drifts into a vacuum (as in, not looking at the effects it'll have outside their own console) and Destiny becomes a "meh" game to them overall.
Like I said, speculation. Reasonable speculation, but speculation nonetheless. And just to jump the gun on a possible response of "what, am I not allowed to dislike the game without being a hater? Maybe I genuinely don't like it"......I'm not necessarily saying that. But it is extremely fishy that 95% of the destractors are Xbox fans. You'd think a sentiment would be equal for a game that's multiplatform (for example, PS and XB fans alike think Call of Duty: Ghosts is mediocre), but nope. Most of the dislike is almost exclusively on the Xbox side for, what most likely is, the above stated reasons.
