I think wrapping it holds it so that it comes out more dense. I've don't both, wrap and unwrapped and the unwrapped tends to 'grow' a bit where the wrapped does not. This has been my experience.
I'm not sure about the kneading part...I hate to knead and it's the reason I don't make seitan that often. Maybe I'll try it your way and skip the kneading.
The best seitan I ever made was when I cooked it about 30 minutes then had to leave to go to my daughter's house. I brought it with me and continued to cook it there for at least another 30-45 minutes. It came out really good!