I too would be interested in knowing whether the default version of Orca/At-spi in 7.3 works with Firefox/Iceweasel. Having to source an older version of these from Debian Squeeze has been my biggest disappointment in 7.2 since it prevents me from booting from CD and quickly having a working web browser whenever my experimentation borks my harddrive install(and I don't know enough about re-mastering to compile my customizations into a CD-rom and most of the tools for simplifying re-mastering seem catered to the sighted).