The good instructors would/should distinguish the necessities verses the optional/fluff. This is what helps the student understand how to elect or reject the ways of various schools. Unfortunately, few instructors are able to teach this way, even once in a while, party because they were not taught that way and partly because they just don't know. Some "coaches" do a decent job of it. For instance, some necessities are the ability to dance on one's own feet, the goal of moving smoothly (even if snappily), the usage of good timing, the maintenance of good connection, etc.. As far as footwork in ECS, the important thing is to aim for a nice body "bounce" that has more movement at the feet than the head, all the while having the feet "carrying" the body and head at the proper angles. The typical variables are the amount of body swing (which correlates to footwork/legwork such as distances between steps), the amount of knee action, the amount of topline bounce/swing, etc.. At some point, with enough good practice, one should be able to strike a balance between all the factors to start dancing very comfortably without straining. This will take countless hours of training (and perhaps even some injury), just like in learning how to spin. OTOH, there are plenty of "ECS" dancers that can barely lift their feet/ankles off the floor, especially as they age, but they have plenty of fun anyway.