Yeah biased is a strong word. What I'm really alluding to is that I think you really only see this pressure on reviewers to rate Nintendo games higher because you're not really interested in their games.
There will be no HD Wii unless it's just a machine that upscales current games and then why bother? I mean are you going to pay another $250 or $300 for a machine whose only purpose is to upscale Wii games? Nah. (Think playing PS2 games on a PS3.)
Plus WiiSports is winning people over with N64-level graphics. Why do they need a hi-def machine? I think this is perhaps an inside joke at Nintendo. 'You say we need hi-def graphics? Well our (WiiSports) pack-in not only doesn't have higher tech graphics than the gen before, it's no better than graphics 2 generations ago
People keep thinking the Wii will fade because they think it's all about the horsepower. But again they forget Nintendo is winning with N64-level graphics in WiiSports. And, btw, according to Nielson ratings, it's the upscale homes that are actually buying the Wii too. So the appeal is not just because it's affordable either.