Hussain Bhai ..I dont think Shortest route Could be the Reason. Even Howrah & Sealdah rajdhaini has diff route. & One of them run via longer path.
But agreed, WR has very less complex route, mostly linear path & Fast track.
Where as in CR , every train going towards Nasik is crawler up to Igatpuri. But still CR deserved 1 Rajdhani, after all CR is oldest railway zone.