I'm pretty sure it can be. It would need to listen for touch events (in the background) that originate at the very edge, then provide an animation of transition between windows, as well as to switch UI contexts.

Another thing that might work, is a four finger gesture, to zoom out all running apps for a quick tap to select what you want. This is pretty common for desktop UIs and I think I would prefer it to cycling through a bunch of apps, especially considering that Android apps don't close like traditional apps do -- there is no user requirement to close an Android application.

In either of these schemes, though, you're going to be utilizing at least the same amount of clicks to get to what you're looking for. In fact, with the swipe-to-select, you can use far more on average.

The HC way of app selection is not terribly pretty, but it is very functional, and requires very little brains to understand how it works. It could have been implemented a little prettier, though.