A local ap could have a local buffer and use that to enable good 1080p over wireless. Also I would love to have the XBMC interface. scrolling with R/L being able to easily FF through intros, etc.
It would be nice to have the application running on the PS3 with it's own custom interface. I use PS3MS myself and it is pretty good, however there are drawbacks. Namely scanning for new files on share drives is a little wonky. It's sometimes quicker to reboot PS3 MS in order to see new files. Also there is the lag that is takes to transcode and the occasional hiccup in 1080p playback.