I rode burton 3 strap on an asym air waaay back and was amazed by the improvement to edge control with the glorified sorels of the time, my Merrel super comps negated my need for highbacks or 3rd straps, no more stoner rigged duct tape and skiboot liners and tongues.
I wouldn't be suprized if somebody doesn't come out wit an optional 3rd strap lockable highback, now that carving is cool and they'll need the latest and greatest newfangled carving system to keep a marketing edge in selling upgrades for the laceup 1 season boots every body loves.