I normally buy all consoles but there is something about the wii u that doesn't suck me in, it feels like to me that they have finally decided to join this gen it doesn't feel like a next gen console to me..
It seems the people who got the Wii for "family fun" don't find anything of interest on the WiiU.
It's more a "classic" game console and the screened controller doesn't change that.
And the people who didn't get the Wii are not interested either because they want more power and "realistic" games and full developer support.
So they are left basically just with Nintendo fans and the "open-minded" gamer.
And even among the fanbase there's a divide, i.e. some like the concept of the system while others don't.
It will maybe take more than just a stellar 1st party/exclusive line-up of games to push this system into more homes.
It's a new system and will be regarded as such. I don't understand why people always cling to the past when estimating console sales. We have seen in the past that if the predecessor sold bad or great, it has seemingly no influence at all on the next console of that company. The Wii U doesn't need to attract Wii owners at all. It's a different console. I do see 'concerns' in that the Wii U is not super powerful and that will indeed turn some people away. And it is not marketed to casuals at all for now. I don't think that they are very interested yet either. So I think you're right in that this leaves a significantly smaller market than the Wii, but let's not forget they do the most important thing right: They make awesome first party games. I think their sales will be fine, if you do not compare them to an anomaly like the Wii.
Now, their competition are either going to fight an impossible battle with the PC if they are powerful, or they will have to beat Nintendo at appealing to casuals. I think both of those options are not too good either. They should probably be more concerned. For some peculiar reason the western media only depicts Nintendo as doomed, while their competitors are exciting and promising? I don't think that they know what they are talking about.
The Wii U will probably be a success in the end, but more likely in the way that the gamecube was a "success" as opposed to how the Wii was a success. Maybe a bit better than GC level.
I always thought it would sell significantly less than the Wii, but I'm still convinced it will do significantly better than the GC (my favourite console of all times, btw). Let's say it again : the WiiU has as of now already sold about 20% of total Gamecube sales.