As edgy is in deep freeze mode now, I don't think that 6.10 will ship wpasupplicant 0.5.5-2, unless there are compelling reasons to do so.
About adding further information to interfaces(5): Sure! -- Unclear/misleading documentation for /etc/network/interfaces extensions https://launchpad.net/bugs/44315 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs