I'm not a Dash 8 -400 pilot but I do have a lot of time on the -300 series.
I believe many of the shortcomings of the -400 series were deliberately "built in" to maintain the common type rating with the -100/200/300 series. Some of these "problems" can be switched off by operators who only operate the Q400. These include such as the independent heading bugs, the need to arm ALTSEL and the way airspeed and V/S is presented on the PFD (Instead of the tape style display operators can chose a round dial presentation identical to the -300 series).
Maybe you could compare the Q400 avionics with the SAAB2000? Both aircraft were faster, more advanced stretches of an earlier model, but one manufacturer chose to maintain commonality with the parent aircraft while the other did not.