What are interesting reasons for wishing to do graduate work in the
field of control systems especially robust flight control systems?
Safety, technological, career-related, human-related, economical
reasons and
others are what i am searching for.

I think you got the important ones. Employment oportunities will
likely be brisk the rest of this century. Not true of most disaplins
which may be replaced by your systems control and other IT technology.
Most jobs will be day shift with weekends off. Better than average
pay. Good background if you decide to do something different latter in
life.   Neil