Darryl - interconnecting the ailerons can lead to a very serious form of flutter. If the wing is not stiff enough in torsion the ailerons act as servo tabs and cause the wing to twist. A down-going aileron causes the attached wing to twist to a more negative angle of attack and so the wing bends downwards. Because the other aileron is connected and operates in the opposite direction, the other wing bends upwards. The entire wing thus takes on an S shape. This resonant mode has a low frequency compared to other modes and will therefore occur at the lowest airspeed. It is very destructive and usually results in one or both of the wings breaking off somewhere near mid span, often at the corner of the aileron cutouts. It is a consequence of the mechanical interconnection of the ailerons. It should be noted that the presence of a servo attached to the interconnection should prevent motion from one aileron being transmitted to the other. In reality, this is not the case. In a resonant event it is most likely that the servo holding power is over-ridden by the forces involved and the servo thus acts only as a dampener. Furthermore, any free play in the linkage system will allow a small amount of movement to be transmitted from one aileron to the other at all times and so contribute to the problem.

Interconnected ailerons do not cause control forces to be neutralized. Each control force, whether the control is deflected up or down, results in a torque restoring the control surface to its neutral position. Thus the up-going aileron and the down going aileron both create restoring torques in the same direction at the servo. The servo must drive both ailerons against their respective restoring torques. There is no "free lunch" in nature.

Interconnected ailerons do cancel out the effects of G loading, as you say, but let's put some real numbers to the problem and see if it is worth the trouble.
A large aileron I have here is 60cm x 8cm and weighs 43g. Since it's cross section is triangular, its CG is at the 1/3 chord point, which is 8/3cm from the leading edge.

The torque on the aileron due to G loading is therefore 0.043x8/3 = 0.115kg.cm/G. If this airplane were pulling 10G (a lot), the aileron torque due to this would therefore be 1.115kg.cm. A suitable servo to drive this (huge) aileron is rated at 15kg.cm, so the effects of G load induced torque at 10G is less than 7% of the servo's capability.

Using one well know servo torque calculation formula, this aileron deflected 45deg at 100kph requires a servo torque of 13kg.cm, so the selected servo is only marginally capable of service and in practice a larger servo would be more prudent, in which case the G load induced torque would be an even smaller proportion of its capability.

Considering the very considerable advantages of independent servos driving ailerons, I would live with the 7%.

I would also like to know how a low pressure region BEHIND the wing manages to keep air attached to the ailerons (AHEAD of this low pressure region). I certainly never saw such a thing in any of the wind tunnels I worked with when I was young.