Not sure I expect much more from the current Band given hardware, design and screen limitations but I do expect they'll have a more fully developed "watch" version of Windows 10.
During today's keynote they had a slide showing the broad range of W10 devices, from the giant Surface Hub to Xbox/Tv, to desktop, laptop, 2-in-1, tablet, big phone, little phone, and maybe a Raspberry Pi. Basically from 3 inches to 85 inches, plus Hololens. I just can't believe they'd work on bringing Windows to all of those different sizes and form factors then completely exclude smartwatches.