Microburst2002;
I agree with large parts of what you wrote but, at the risk of sounding pedantic, I would like to add two distinctions:
Moments of inertia are not directly proportional to weight because they depend on mass distribution. If the mass is mainly carried in the fuselage, variation of gross weight will have little effect on rolling moment of inertia. If, on the other hand, the wing contains a large mass of fuel in its tanks, then reduction of that mass has a large effect on the moment of inertia about the longitudinal axis.
Secondly, I would prefer to distinguish more clearly between angular acceleration (usually expressed in deg/sec/sec) and roll rate (deg/sec). At zero roll rate, angular acceleration is, as you write, rolling moment from aileron deflections divided by rolling moment of inertia. The angular acceleration produces an increasing roll rate, which means that one wing moves down, that downward velocity increases the AoA of that wing, and hence its lift. Together with the opposite effect on the other wing, that produces a rolling moment opposing that from the ailerons. At some point these moments will cancel each other and roll rate will not increase any further. At constant roll rate the moment of inertia is irrelevant.
regards,
HN39