I don't think either of these are really all that common anymore.
After seeing the PS4/One launch, the only Nintendo fans I've seen on any section of the internet who still expect Wii U to dominate are in the unity thread. And even then there are very few people left other than JL. It seems like this was mainly prevalent pre-E3, not so much at this point. I do wish there were less people making excuses for some of Nintendo's poor decisions though.
As for the Xbox fans, I'm pretty sure the Xbone has more big exclusives coming this year than the PS4, plus more marketing and the new Kinect which has been fairly well received. Expecting it to do well this year isn't all that crazy, is it? I mean even the prediction in your sig would be a pretty great first year.
Much like Sony fans with the Vita, the few remaining Xbox/Nintendo fans who expect domination will lose faith soon enough.
