Excellent news! I personally think unity is terrible - and it's objectively lacking in several areas, multi-monitor support particularly.
The Ubuntu phone thing was a nice idea, but obviously never going to fly, so it's nice to see canonical putting their efforts where their actual users are.
Wan't thinking about multi-resolution or HiDPI - or other technical 'support' - but actual ergonomic use of multiple-monitors. It's lack of customisability in the placement of things, as well as the anachronistic global menu bar, mean that using it with, say, 3 large monitors of pretty sub-par.
The Ubuntu phone thing was a nice idea, but obviously never going to fly, so it's nice to see canonical putting their efforts where their actual users are.