Are there any good examples / case studies of mobile applications revamped (improved UX) that have a higher conversion due to the UX adjustments?
Most studies on this seem to come down to navigation, as that is usually the biggest difference between mobile and desktop variants.
Conversion for mobile often boils down to how you present certain choices in the login and check-out/shopping cart steps. Asking for private data or app rights (such as facebook etc) in the wrong way can scare people off, killing conversion.
Not exactly what you asked for, but I did find 2 helpfull navigation case studies: