The external shape of the Sentinel is bought and paid for in terms of design, performance and handling qualities. For these bespoke users the clearance of the external payload shapes is quite an investment and modern types (as opposed to the more forgiving and over-engineered older types) are more difficult to modify and clear. In these terms the external shape of the Sentinel is more marketable to the niche customers looking to update, replace or launch new capabilities.
I always thought that the extra bumps in the Sentinel fuselage allowed the Army Officer to fit in his horse when the aircraft deploys: the front hump behind the flight deck fits the head while the canoe allows leg room and a drainage channel for the droppings (for the horse - not the officer).
