I've said it at some point... The next thing for wfp is a return to tank hose for water reclamation (if I've spelt that right)
A number of years ago Ionics had a system like a carpet steam cleaner without the steam. It was supposed to be for internal wfp work. You cleaned the windows as normal but incorporated was a vacuum hose and attachment that stucked the dirty water off the glass.
It was just too heavy and it would also have internal cleaning complications such as electric lights, switches, door mounted electrics and electronics etc.