So you say these two games sold "only" 6 million copies and didn't show any big legs because people were disappointed by their quality, but couldn't be the deeper truth that many of Nintendo's "core" fans disliked both games not only after, but already PRIOR to release, because these were not the games they would have preferred (e.g. new 2D or 3D Mario platformer, new Zelda, new Metroid)?
Of course I can't prove it, but I have a feeling that many of these 6 million copies were sold to gamers which were new to consoles, i.e. gamers which are presumably unbiased by default and are often called "casuals" on forums like this.
As you mentioned Blizzard, here's a hypothetical analogy: If they hadn't announced Diablo 3 and Starcraft II, but The Lost Vikings 3 instead, I bet their devoted fans would have torn them apart and the game would have sold nothing compared to Blizzard's usual standards, no matter what quality it might have had.
To get more on topic, as this is a thread about the efforts of Wii's 3rd party developers in the first place:
You said "The big difference between Nintendo and third parties is that Nintendo had the reputation while many third parties actually build negative reputation with their early games and even some of their big franchises have a harder time selling now because of lazy efforts early on".
This again doesn't make much sense to me as all your argumentatio seems to be based only on your own point of view, i.e. it's a "core" gamer's argumentation with all your knowledge about (Nintendo's) gaming systems. A good portion of the 50+ mio. Wii owners are first time console owners. These people have probably heard about Nintendo's good reputation, but I'm sure most of them don't know or care about the reputation (or even the name) of 3rd party developers. So how can there be negative reputation of 3rd party developers, if many people don't even know the name of the game company they bought their game from?
If many 3rd party efforts are lazy on Wii, are many 3rd party efforts lazy on PS3 and 360 as well? If this question can be answered with no, who's to blame?
The 3rd party developers? Of course.
Nintendo? I know, lots of people will disagree with me here, but I think Nintendo is at least partially to blame as well.
I'm not the biggest Microsoft fan on earth, but I think this gen (in fact it already started last gen) they developed a strength Nintendo still misses: Excellent support of 3rd party developers in order to convince them to join their gaming system - and I'm not speaking of money hatting here, but of full support with development kits and own trained staff.
Nintendo is an extremely clever company when it comes to their own business, but I still wonder - especially in the light of the only moderate success of the Gamecube - why they didn't (seem to) understand that, with the Wii, it should have been one of their most important tasks right from the start to fully support 3rd party companies and help them to understand and learn about their new approach, their new console and especially their new motion controls.