I sure hope MS is resting on their laurels on the Zune platform. Their laurels aren't stacked very high in the first place. Also hope they aren't expecting Windows Phone to carry the Zune brand/ecosystem. The compelling argument is in the diversity (such as it is). Until they get phones with 32/64G and 6-8 hours of media life that still can make a call after that, I'm still going to want a dedicated media device. Great that my Windows Phone is part of my Zune stable, but it currently won't replace my Zune HD. Would be nice if my next Zune ran Windows Phone apps and was linked to the same XBox Live feature my Windows Phone is.
P.S. MS, don't discount smaller form factors with physical buttons for primarily music, podcasts, etc. People use these when active and it is pretty tough to reach into your pocket to adjust volume, change tracks, when all you have is a capacitive touch screen.
Sometimes you are the anteater, sometimes you are the ant.