Trackpad vs Mouse
Aside from a couple minor errors (3-finger is click-and-drag while 4-finger does the navigation) you're right about the trackpad. On the other hand, in some places a mouse is still the better choice--especially with gaming where you may need to simultaneously drag the viewpoint and click a target just that little bit faster. Touch on the screen itself might simplify the gestures, but at least for the moment you're right hand simply needs to perform more than one gesture at a time which isn't possible on an external touchpad.
That said, I use both depending on need--trackpad for everyday navigation and productivity and a mouse for gaming. Maybe improved game software will change that view.
