Why should it not had been leading the pack? (full disclosure I don't own a Wii, but do own a Wii U and Vita and Gaming PC) It was what the people wanted, that's why it sold the most consoles of all of them. Rather developers cared or not, or had whatever reason for not making their games for it doesn't change the fact it is what the people chose. When you have to lump your system in with the competition to claim victory as if they were one entity then yes you lost that's how its always been.
As to where the Wii U stands I think it will probably finish first in Japan, second/tied for second in the US and last in Europe. Third parties are free to not port their games but to me it's always been crazy to ignore a 3rd of the gaming pie, and people cheering for it seem to not care or understand the reality most of these companies face. there are a set of posters that only pop into threads that tend to be able to be turned into a negative slant, and pile on with me too comments without offering anything to these conversations. It probably goes all the way back to the Sega/Nintendo days when the "war" was hot and heavy, with Sega becoming "cool" and Nintendo "lame." Many folks grew up in that generation with commercials like this:
http://www.youtube.com/watch?v=AmhtW-pdfd8 and simply never lost their fan colors and so still love when they are able to take any news, no matter what it is and turn it negative.
I do think Nintendo needs to consider simply funding and creating their own "mature" FPS/TPS titles, because that seems to be the only games people seem to crave these days.