The problem with a solely dynamic/cooperative approach is that it is a poor teacher of body dynamics. My experience of dojos that emphasize the latter approach is not that good.
Last night I invited a Nidan with 15 years with Osaka Aikikai to observe class at Shodokan Honbu. Afterwards in a private tatami room over the Izakaya consuming beer and ramen we discussed the differences between what he saw and what he does. Discussion means pushing the tables aside and as quietly as possible demonstrating. Their approach, which I will see first hand next week, is to start with a firm grip in order to understand how the body works and then latter to bring in the dynamic body movement. I am not sure what you mean by stationary since nage does move his centre and uke is moved.
Our approach, although we use on occaision, a similar solid grip, is to rely on full resistance randori to give our clue as to what does or does not work. We also use kazushi in just about everything.
Both styles are very dynamic but both work through stages which I would refer to as non-cooperative. The end result is good effective Aikido.
So yes - I agree completely with your post.