Hi Kirk,
If I were to implement such a feature, I would likely do it with HTML since it is so universal. Flash requires a plugin and believe it or not, some people haven't installed it. QuickTime is native on Mac OS X, but has to be installed on Windows. HTML just requires a browser, which everyone has.
I recommend HTML galleries to photographers who want a cross platform browser solution for delivery to clients (along with a README). FWIW Windows XP and Mac OS X come with Flash installed, so you'd only need to depricate it to an older version of Flash Player. That only leaves OS 9 and WIN98

. If you script to drive Flash all then bets are off.
You mention in
this thread PM4.5 will use Peter Berger's EOS Templates. One EOS template allows client feedback - even when run off a read-only CD. Instead of exporting a Breeze Browser text file could it export a Photo Mechanic compatible file? It relies on javascript, as does the Adobe web template that offers feedback.
-- Robert Edwards.