If people have told MS they want it on the feedback site, then they'll at least look at it. If they do release a new controller, i'd get it so they're making money off me they wouldnt otherwise.
It would make sense if the demand is there, they did do another 360 controller with a new d-pad... and the controller S on the OG Xbox
Sure, they'll catch s couple extra buyers, but there's a cost to r&ding and producing a second product line, not to mention actual support for whatever the changes if they're meaningful.
The other examples are true, but the OG Xbox controller was huge, and caused a fair amount of issues as a result. As for the D-pad change, I don't know that I ever actually saw one of those in the wild, so I'm betting it was fairly limited to its creation. Like I said, it could use improvement in a few areas, but they talked it up so much that I find it hard to believe they'd change it. Of course, this gen has been full of that though, so who knows...