Honestly, I think it's just a matter of preference. Some people have larger hands and need the sticks further apart like xbox, and that could feel better to them.
It's not about changing it because that's was Microsoft did. It's about keeping loyal to what their fans enjoy, and what they believe to be a great design for a controller. You may not agree, and that's perfectly fine. Everyone is entitled to their opinion.
Back when they first showed the share button at the reveal event, I didn't think much of it. Now however, I realize it's a fantastic idea. I cant count the amount of times I feel like i had an epic moment in just cause 2, then to be sad because I didn't have a PVR.
It could also be a great teaching tools for noobies. This share button could have a lot of great uses