I dislike this story for much the same reason. This time period is supposed to be "too late for me" Vader. Movie wise it's smack-dab in the film where Vader is at his absolute most menacing and evil.
If this story took place a couple years after Episode III, I might be OK with it, but taking place "between the scenes" of ESB turns it into a wall-banger.
Vader isn't supposed to produce "squee" and "d'aww" moments in this timeframe. Unless the "squee" is the sound of buttcheeks clenching together when he walks into a room.