It would be very useful (and a big time saver) if it was possible to adjust the start date, duration, and completion of the selected task using the keyboard arrow keys.
My suggestion is:
ALT+RIGHT : advance start time
ALT+LEFT : decrease start time
CTRL+ALT+RIGHT: increase duration
CTRL+ALT+LEFT : decrease duration
SHIFT+CTRL+ALT+RIGHT : increase completion
SHIFT+CTRL+ALT+LEFT : decrease completion
This feature request is similar to these ones, yet no progress has been made.