Ok try this, open a few apps. Minimize the view to the little cards. Now drag the cards to the side of the screen till you can't see them and hold. Release them....dont they pop into to view fast! Now imagine you have a way to click the homescreen to view or unview cards.

Also it should hover some cool icons above the cards so you know quickly what they are...this would make multitasking more elegant and I would leave cards open more often to take advantage of the speed to get to an app.

just my thoughts