Well, we've been sort of reluctant to start in on the non-Transformers stuff mainly for technical reasons. It's something we want to do in a very deliberate way, such as a category that is a sibling of the main "Transformers" category. Unfortunately, there's a lot of code right now in the system that makes assumptions about what the root of the tree is (right now it's "Transformers", but after expanding the tree as discussed, the new root would be something else, such as "Toys"). So it's doable, I just need to get to it, and there's a lot of other work I have half-finished I need to do first.
In the meantime, we could sort of cheat and just add a "Other Transforming Robots" (or whatever) category as a child of "Transformers", and move it later once the other work is complete. I'm leaving that sort of decision to Engledogg, as he's the one that will wind up doing most of the work. Maybe if you ask reaaaaalllllly nicely...