i don't think you understand what panning is, in this context:
https://discussions.apple.com/thread/264648?start=0&tstart=0
if Windows has this, i've never used it. every PC that i've worked on, and i've worked on many, if you select a screen size that doesn't match the pixel resolution then Windows will stretch or shrink your desktop to fit.
You are correct - I was using "panning" in the developers context, which is horizontal and vertical scrolling. I can scroll my email up and down (using my wheel) on my right monitor, even when my mouse is on my left monitor - that's what I thought it was referring to.
The only panning in the context you are referring to that exists in Windows machines exists if your hardware supports (check your Intel graphics properties). I've never used it, but my Sony laptop supports it. Now that I know it exists I'm sure I'l find a use case for it, but right now I can't think of one.
Here's a pretty good list of what Mavericks brings, with point #1 and #2 being what were the huge surprise to me that they weren't already supported:
#1: migrate the menu items from the primary screen to whatever screen your mouse is focused on...
#2: allow you to make SOME programs run full screen on SOME monitors ... right now when one goes full screen, they all do.
#3: move the dock to whatever screen the mouse is focused on.
#4: allow the use of any Apple TV connected television to become a second/third monitor and still retain 100% of the features of a wired connected monitor.
The last one sounds a lot like MiraCast or WiFiDirect, just with using an existing device in the Apple ecosystem. I'm sure that's a huge plus for Apple enthusiasts. I've used Miracast with my tablet and phone for presentations - it's nice for slides (and music), but you really can't rely on it for movies. Maybe Apple TV will be different.