Not that this is a reason not to do it, but we'll inevitably have people asking for variant logos (different rotations) when their project's script is represented on the "dark side" of the wikiball. (And if we're being cynical, we can imagine an argument over which view of the ball is best representative of our projects, or most relevant, or most aesthetically pleasing, or what have you.)
My ideal is that the foundation should, perhaps again through a contest, create a 3D-logo for Wikipedia and all 2D-logos created from this logo are then derivatives and could be used for our projects.
How is the legal issue for a 3D-logo?
Ting