To get to the Dock from a fullscreen app, just move the pointer all the way to the edge where the Dock is pinned, then swipe or move the mouse in the same direction again, as if you were trying to move beyond the edge. The Dock pops right up, with no keyboard commands needed.
This is probably the best solution for full-screen apps where you may frequently need to move the pointer quickly to the edge of the screen where the main buttons are likely to be. If it just popped up the Dock when you move the pointer to the edge (as with 'Hide Automatically), it would be a source of frustration.
[crarko adds: It took me a few tries to get this to work. As with many gestures, it requires a pretty light and precise touch. Otherwise you'll just wind up scrolling the window in your fullscreen application (like Safari, where I tried this).]