The Wii is not necessarily bad, it just really only has a handful of good games. everytime someone writes about, i hear the same about ten titles over and over, while the rest is a bunch of minigames in a single game or VS games (which aren't bad, but DLC shouldn't be a console selling point). My big problem with nintendo is the marketing design of the company. All of their main series, like Zelda, Mario, used to be Metroid, and SSB, the only make ONE GAME per generation. Thier idea is to make one to maximize it's sales on that console, which is a giant middle finger to their fans, it really is. This wasn't as noticed in past generations of Nintendo because they still had a decent third party developer base that made good games, where as now none of the good third parties want to design games for them because it's too much of a hassle, so all your left with is released main series games and random games that generally aren't that good. My final reason why Nintendo isn't that good is that it made a system that is geared to the casual gamer. And i don't say this because i believe "hardcore or die", it's because it's a bad marketing choice. The casual audience doesn't play their system, every day, every week, sometimes not even every month, and they never keep track of releases or an eye out for games they like. Most of the people i know who don't really play games but bought the Wii haven't played it in months except for the once in a while when a friend comes and they through in Wii Sports. So, no, the Wii isn't necessarily bad, it's that the first party isn't making games, the third party doesn't make good games because they don't like the Wii, and it's target audience really doesn't give a crap. Sidenote, i found it hilarious when the Wii released it's improved motion sensitive thing, because the first thought through my head was, "shouldn't they have gotten it right the first time?"
