As long as they don't have a brain explosion like at PS3 launch with the dropping of rumble then I'm fine with what we have.
There has never been a time when I've thought "stupid controller I wish it was different" when playing a game.
One thing I think would be an improvement, without being a wholesale re-design, is the ability to swap D-pad and left analog stick positions for those who like their left analog stick in the asymmetric position for some games. Though perhaps that would require a re-shaping of the controller to avoid having the analog stick end up too close to the handle. Personally I don't mind because the few times I play FPS I'm more than happy with the left analog stick being where it is.
Edit: Perhaps there is an ergonomic reason to change left stick positions, but it must take a large number of hours of continuous gaming for the ergonomics of the controller to become a significant factor. The overall ergonomics of the controller are fine for me.
Oh another suggestion: sweat resistance/absorbtion on the tops of the analog sticks, that does get annoying when my sweaty thumb slips off the analog stick at a crucial moment.
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