Think about the geometry of the dish for a 360 coverage.
the VT and HT will obscure the rear view, so the option is always to avoid placing an antenna facing directly rear ward.
for optimal coverage 360/3 = 120 deg would be enough for electronic steering of the beam.
so you really can only place the 3 antennas in an inverted triangle.
an inverted triange is not good for aero or stability or aeroelastics.
if it wasn't the qualified radome ellipsoid shape, wouldn't there have to be an extensive
qual program to prove out the aerodynamics and drags counts? it was probably easier to stay with the same shape and just change out the internal components