[bztzt]

Definitely agreed. Another interesting problem for the near? future is multi-device window management - can you use the collection of devices and screens (whether phone/tablet/desktop/whatever) on hand at a given moment as a kind of ad hoc multimonitor workstation? What about when multiple users are involved? (of course all of this is a systems/OS and privacy/security challenge, as well as an interaction design challenge)

I sometimes get the impression most people now think of window management as either a solved problem and/or one rendered irrelevant by the rise of "mobile", but it's quite the opposite IMO.