HeedM,
Coriolis effect is an inertial force described by the 19th-century French engineer-mathematician Gustave-Gaspard Coriolis in 1835. Coriolis showed that, if the ordinary Newtonian laws of motion of bodies are to be used in a rotating frame of reference, an inertial force--acting to the right of the direction of body motion for counterclockwise rotation of the reference frame or to the left for clockwise rotation--must be included in the equations of motion.
The effect of the Coriolis force is an apparent deflection of the path of an object that moves within a rotating coordinate system. The object does not actually deviate from its path, but it appears to do so because of the motion of the coordinate system.
I don't think the above (which was gleaned from an internet search) can be confused with conservation of angular momentum.
The blades C of G is trying to move towards the rotor hub as the blade flaps up - the only impact of coriolis would be the apparent movement to the right as it tried to do so (counterclockwise rotation viewed from above).
If you assume (rightly or wrongly) that relative to the rotor system this produces a leading tendency of the blade as it flaps up then that is why you need to modify the effects of conservation of angular momentum with this term.
Does the blade really try to move forwards on it's hinge due to coriolis or is it just apparent movement relative to the rotor hub?
Newtons Laws governing conservation of angular momentum would argue that the blade will speed up as the C of G moves inwards but would not explain why.
Maybe you are completely correct and Coriolis effect is the driving force behind the C of A M - I dunno I'm not a graduate just a pilot so if you do know please explain.