One of the biggest problems with ajax is useability without javascript and a heavy reliance on CSS which can be frustrating when you are trying to get advanced features working accross as many browsers as possible. IMO, the admin area is the LAST place you want ajax, simply because of the number of factors that can go wrong, and leave you unable to administer your gallery.
I think Ajax will be much better supported in the next generation of browsers, and it might be worthwhile to look at then.
If you feel strongly enough to do some research, I would like to see a proof of concept, perhaps you might convince us it would be worthwhile for 1.5. The proof of concept should show an IMPROVEMENT to usuablility over the current methods, not just a DIFFERENT way to do it. There's no point to change for change's sake.