Re: static vs. dynamic waza
Good points Jon,
Uke understanding his job is very important, I would say that it's one of the major stepping stones in understanding what we are doing in the techniques.
For example, ura waza techniques usually require uke to give forward, pushing energy, while omote technique requires uke to have weaker, retreating energy. If you mix the two up, the techniques don't work correctly, but in the proper context, they work like they're suppose to.
I often think having the more advanced student take the ukemi first (when paired up) makes this go much more smoothly.