Well looks like your first mistake was taking the film to seriously to begin with.
Secondly, you missed the whole message of the film entirely, which I thought had a great impact on creativity alone. I remember always being frustrated as a kid how the instruction books for any LEGO set always had sample images on the back of alternative things you could make with the set, but they never gave instructions on those. Thinking back, now I see why they don't. Because they want you to use your own creativity and imagination to figure out how, or make something else entirely. Sure, save the world is a recycled plot, but it becomes clear there was another message intertwined in between, and in such an appropriate manner without turning the movie into just one big obvious ad to get you to buy LEGO sets.
For that I felt the movie did solidly on quality. Not legendary, but solid.