FS,
Not sure of battery power on STBY. I've never seen the 60 minute number for two. As for the IFSD, the extra time is nice, but without any Nav or Comm source, the 737 is less redundant than other aircraft. There seems to be a common theme that it's never happened so it's not a problem. If so, perhaps the other fleet types can deactivate the backup generator option of their RAT's to save maintenance costs.