Beyond that, I think it's just some of the subtle ease of use things. I strongly prefer OS X's implementation of virtual desktops over anything I've used on Linux; the UX is just smoother. All in all, all the Linux desktops just end up feeling a bit more fiddly to use, which leaves me feeling like I'd rather have Aqua than any Linux desktop as my main UI.
Installing userland software also gets a bit obnoxious on Linux, owing to there being eleventy-seven different package managers to deal with, none of which include everything you might want, so you're inevitably stuck dealing with some bits manually, which, again, is just an annoyance. And heck, 20something years since dpkg first hit my radar I'm still having to fiddle with dependency conflicts, which is something that I've never experienced with OS X style bundles. I'll gladly swap the minor loss of disk space that comes with not relying on shared libraries for the convenience of drag-and-drop installation whenever possible.
I find the best Virtual Desktop (Workspaces) implementation to be that of i3wm. I can spin up as many as I want, on the fly, using a keycombo and even ask apps to open up on a specific workspace.
On the other hand, I really agree with your points about large touchpad, good battery and portability. Also include SSD and the ability to swap out the CD/DVD for another disk drive.