This seems like a pretty clear improvement in the interface, at least
for novice users, and as you say it can be deactivated for more
experienced people. As a proof of concept it looks pretty great. I
would say if this were going live, make the defaults be to not show
the header or footer, and only have this active in the mainspace. As
people are experienced more they could turn on the full editing view
in their preferences.
Judson
http://en.wikipedia.org/wiki/User:Cohesion