Someone sayed: " I believe that the outside wing will have a lower angle of attack because of the outside aileron being deflected up due to having to hold off the bank. "
That depends on the Type of Aircraft and the Maneuver flown. Lotīs of Aircraft donīt need oposite aileron during turns and some need aileron into turning direction to hold the bank.
But think about this:
"As the airspeed bleeds off, you will need to apply more and more right rudder to maintain coordination ( to compensate for the helical propwash). Coordination is very important, because even a slight slip angle will cause one wing to stall before the other. This could easily result in a spin, and even if you don't get a full-blown spin, the sudden change in bank angle is pretty unpleasant.
Also, in this high-power low-airspeed situation, you will need to apply steady right aileron (to compensate for the rotational drag of the propeller). Note that the roll damping goes to zero at about the same point where the stall occurs, so you will need to intervene rather actively to keep the bank. The standard advice applies: make sure you use the ailerons and rudder together. Because the airspeed is low, you will need a whole lot of rudder deflection to coordinate with a small amount of aileron deflection, and indeed right near the stall you can quite nicely control the bank angle using the rudder alone. Imagine that the left wing is about to stall. By stepping on the right rudder pedal, you can swing the nose to the right, causing the left wing to speed up and become unstalled. During this maneuver, you might want to lower the nose a tiny bit, so the right wing, which is swinging backwards, doesn't stall."
by John S Denker, see how it flies
I think most of those wingdrops during turns are caused by improper coordination.