you....didn't read the op? Ive talked about all the things you've mentioned.
as well as the toggle on/off option.
1 thing i haven't talked about is the code, but i don't know enough about it to paly smart there....BUT! i know the code has already been implemented for stuff like the compass. so its easy enough, and works great.
Sorry, I skipped over a Few of the spoilers. I do think this is well thought out. But again, I do come to say, this is not really needed, and there are some more important things right now on the schedule of mojang.
I don't see why this is necessary. Yes, it would be nice and all, but it would cause more lag, in my opinion. If it were implemented, i would want some way to shut it off, and only show a "default"
The other thing, is it worth the coding that would need to go in. Because there would need to be some coding involved for the refreshing the skin, showing the changes to other users, etc. etc. So, would it really be worth all of the trouble?