The drawing app seems like a no brainer, and since Nintendo showed a drawing app of some sort in their WiiU reel at E3, I'm sure it's only a matter of time before it becomes a reality.
As for the others, what I would like to see most is the live gaming app (it boggles the mind with how fast some of the runs on the Rayman app are, and I would love to see how they are done), the miiverse polls, as they would give Nintendo and others more ideas as to what the customers want, and the Picture/video editor, media player, and music apps would add extra layers of functionality to the system that I know I would use frequently.
Also, my Mii is on the Gamepad on the live gaming app section. I guess that means I've finally made it.