I challenged myself to only use the most basic blocks of each category to make all the rest. So far, I've completed the motion and control categories to my satisfaction. If you have any suggestions for block implementations, feel free to state them!
Interesting that you can strip Motion down to nothing, but can hardly make a dent in Control.
I don't think you can reduce = to < and >. That's okay if you're comparing numbers or text, but = also has to work on other data types, such as lists or scripts, which don't have that kind of ordering.