I agree with the OP that the radar should show approx. altitude as was possible in reality. The radar range should also be increased substantially, perhaps to realistic values. As it is now, there is zero point to intercepting medium to high alt bombers, and they get a free ride; by the time they show on radar it is way, way too late to climb and intercept.
Flying bombers is difficult enough as is. Clever route planning and altitude are about the only true defenses a buff player has.
They do get "only free" ride by those fighter pilots that only care to up if a con actually enters a dar circle. If you read the whole map, you will quote often be able to identify & intercept buffs long before that.
Now if you implement the altitude component, it will be just easier for the fighters, and it will add nothing for the bombers. And no need for the fighter to guess anything, easy to judge from the tower if it's "worth" to up or not. And as already mentioned, giving the fighters a convenient altutude readout will result either the buffs being higher and higher, or NOE.
And this is not limited to buffs at all. The same goes for enemy fighters or jabos.
And for the "realism" thing... almost nothing about radar in the MA is realistic in any way. The radar in AH has a gameplay function. "Realistic" radars would work almost across a small map, giving not only altitudes but also speed and type estimations.