I can't stand the "it started as a Wii game" argument either, especially when a 5 person team with no recourses (Shin'en), managed to make an eShop game that looks a lot better than Pikmin.
Shin'en's game is a glossy shader heavy shooter with a few levels. Pikim is a retail game with a large world. Like all Shin'en games, it's basically a "look what we can do" tech demo. Note that I'm not implying this as a negative point about Shin'en.
Besides that point, the "it started on Wii" shit goes the other way. Pikmen 3doesn't look like an upscaled Wii game. That's raw trolling. There's no need to qualify or defend how the game looks. It uses a lot of effects and runs at 60fps. It has very attractive design and art direction. It looks rich. Pixel counters turn around and march off to buy a new video card for their PC, this nonsense is not needed here.
The "Nintendo is lazy when it comes to internal productions" is old, trite, and tired. Whether anyone likes it or not, this is what Nintendo does: apply an appropriate amount of production value to make a game look nice. Whether that's a little or a lot. They do not play the game of "let us sell games based on graphics and impressing a thin slice of geeks by advertising our game has the most expensive audio-visual production to date in gaming."
When a game can use heavy investment in visuals, they readily go there. But the truth is, if you're a pixel counter and all that matters to you is feeling reassured that every game you lay eyes on pushes technology to be bleeding edge without regard for the return on it, Nintendo is going to confound and frustrate you with their sensible and reasonable approach to game development that allows them to enjoy remaining profitable on the software they release.