Juvenille, it was a little at times. It is a movie about Legos after all so you don't expect it to try to take itself too seriously. It's no "Wolf of Wall Street", but it was still well executed and a lot of fun.
It was, but it was also a commercial that you could enjoy. Then again, I don't think Lego needs as much of a better commercial than the weight their name already has.
LEGO is... wow. LEGO had more of an influence on humans than Barbie. They don't really need anymore publicity to become well known. Though I think most of the adults that watched it went out and bought a LEGO kit :}
I think the key difference between those is that the movie had the fact they were Lego was central to the plot instead of it being the medium for the plot.
What I mean is how the writers focused the stories. In the made for TV Lego stuff. It's more like a story is being told to fit the line of Lego kits, but the characters and setting happen to be Lego. It could work by itself even without the characters being Lego. In the movie, the fact that the characters are Lego is actually central to the main plot, and depends on them being Lego in order to work.
That movie was a giant LEGO commercial.
Wil check then; if it's as awesome as their video game series XD