How does it limit customer choice?
It prevents people from buying a phone that has everything that they like about the iPhone, but is also an improvement on the iPhone. This is exacerbated by Apple's own policies that hinder their customer's ability to make their own improvements to their own property.
I wonder whether a larger issue may be that people want the GUI to be consistent, even between different models and makes of phone.
It seems counter-productive to have phones with different GUIs for the sake of avoiding patent infringement. The result is the consumer wastes time re-learning how to use the device.