RAT 5
I think you put your finger on that one.
For example: I know that I'm one of the most 'Autos off' pilots on our fleet. But I usually keep the FD on. This is because, if we get a GA the FD will not come on if you have already switched it off. So you're looking at a raw data GA with four stages of flap to get in!
I had a situation about a year ago when (due a genny fail) we had no FD or autos (climbing out of Frankfurt).
Even though I'm a very hand flying type, I found the lack of FD , coupled with our troubles, to be quite a lot to deal with.