well, here are my suggestions. As far as this being a design company thing...I don't think it's quite there yet. I mean, i think your type is too big. If anything the "what are you missing" should be the biggest thing on there (i'm assuming it is like a tagline) and the "missing designs" should be smaller, and somewhere a little less in the middle of everything. I mean, if that is the name of this "company", shouldn't it be a logo? Have you tried coming up with a logo? To me, that would be my first step before designing a flyer.f
On to the concept...
concept is good, but you need better photography. The tree pic is quite nice, but to me it doen'st have anything to with this. The puzzel pic to me is a little better, but is also very expected. Think outside the box a little. Think everyday objects that without one part of them would look completely wrong. You could even take it even further and make it about color. Like a picture of an orange, that is in greyscale. Not quite as pretty, or obvious, but would still get the point across. I mean, people would recognize it as an orange...but without the color it would still look like it was missing something. You could even tie that into your website and have a simple flash intro that showed the b&w orange and asked the viewer "what are you missing?". Then the orange would pop up in color and immediately people would think "color". This could even be a series, where you cover other design principles. I don't kow...just thinking outoud.
-JE