I have another Lion-specific thread going now
No, what I'm referring to is being able to list my spaces, (yes, now in M/C), pick and steal an app running in one space and move it from that space to another, in addition to an app already running in the target space.
For example, on desktop 2, I have TextEdit running with information I now want to see next to an application I'm running on desktop 4. On the old OS you simply showed your spaces, and click-select/dragged an app by its minimised self to a new space.
EDIT: OK - got it... you launch M/C and choose a new desktop. Start the nested app on that desktop and 3-finger swipe again. It shows it minimised in the new "current" desktop at the bottom as a floating layer, which you can then re-drag to whatever desktop you want. A bit different, but nice once you get the gist.