On my two earlier API proposals , I'm going to take a step back on the first one about combining the apps.Driver class into apps.Fop. Joerg's thoughts that the API wrapper/class and application wrapper/class should be distinct is weighing on my mind; in the future we may find it beneficial that we have them separate. Also, "Driver" has a long history with our application that disturbing may not be worthwhile.
The second issue I'm still unsure on, although I moved FopPrintServlet from using XSLTInputHandler to JAXP.
That's ok, now that JAXP is more or less ubiquitous. The XSLTInputHandler predates JAXP by quite a bunch of months.