Amen. 5 and 7 AEB is one of the most useable day-to-day improvements I have enjoyed with the 5D Mark III. With the 7D, I need to take 3, then go into menu, shift it all, and take 3 more. With the 5D Mark III, I can lay a -1 to +1 range on thirds. Should not require any technology changes - just firmware.
This was certainly one of the upgrades I was hoping for as well (why wouldn't canon do this - it must be a fairly straight forward change?). There is a relatively effective go around though: pre-set C2 and C3 to the desired brackets, then it's just one click from C2 after your first three shots, to C3 - not perfect, but better than diving back into the menu.