It'd be difficult to include all the features I'd want on a controller. Too many ideas overlap to create one ultimate controller.
Valve's modular controller patent, not dissimilar to Mad Catz' MLG one, is great for PC gaming where you can swap the right stick for a trackball/trackpad but it might not work for consoles.
A controller screen is a great idea, maybe smaller than the one on the Wii U would work better, but you lose the break apart comfort and pointer controls.
More shoulder buttons are great for dual analog/trackball/trackpad controllers since you won't have to lift off to hit the face buttons. One of the great things about pointer controls (best exemplified in Infamous 2) is how it allows you full access to the face buttons without sacrificing camera control. But pointer controls still have issues with turning.
Which reminds me how huge of a f*ck up was the way in which Sony decided to manage the controller. Sony should have included the thumb stick in the move controller and sell them in pairs. So one move functions as the nav controller. The advantages for doing this in terms of potential play mechanics are gigantic. Btw, im not saying that the user would be using the stick and aiming with one move controller because i know is confusing.
Razer Hydra did that.
Although I'm not sure if they ever released a version where both controllers aren't tethered. The button layout, and lack of d-pad, also make it unsuited for certain types of games. Still, that's what Sony should have done with the Move. Of course, Move has a giant ball on top so I shouldn't have looked as nice.
If anyone wants a feel for how a hybrid analog and pointer control setup works, Time Crisis 4 with the Guncon 3 gives you that. I'm not writing it off based on my experiences with that, but I'll say people severely underestimate the dexterity required for that control style.