I've implemented Stefan Bauer's awesome post on customizing list forms here: http://www.n8d.at/blog/make-custom-list-forms-centralized-manageable/
This essentially shows how to separate the XSL from the DVWP to allow easy updating of form layout. I love it and it's working on my custom List forms for Edit and New.
HOWEVER, for the DISPLAY form the XSL isn't updating after the first iteration of customizations. It sees the initial customizations, but no updates thereafter. I've cleared cache and ensured that the XSL file is publishing to a major version and have eliminated customizations to ensure that it wasn't something I did.
I'm using SP Designer 2013.