But the issues you describe isn't XML's fault, it's poor oversight and lack of consistency from developers. Does anyone have an architect or API designer hat at your company? They should be responsible for designing the XML structure, setting rules on where values go, etc.

This is an issue that you will have with every kind of data transfer / representation tech, be it XML, JSON, protobuf, etc. Someone needs to have ownership, someone needs to set a standard, and everyone working on it should stick to that.