Maratis - Simple 3D Game Editor

Maratis is a simple and visual game development tool designed for artists and developers. Tested on Windows, Mac and iPhone. [full feature list]

Simple is good and Maratis' Interface is very pleasantly simple. I suspect the same thing (without iOS support) could be achieved by providing a simple blender UI setup and a few instructions. The default Blender interface is quite intimidating for beginners after all.