IO540 i think you will find that the principle of this operation is far simpler to explain then your suggestion of a gust alleviation device or Checkboard’s suggestion of Lockheed’s DLC, which as the name suggests is LOCKHEED specific
For starters DLC was design to allow for smoother approaches a constant deck angle by deploying Spoilers symmetrically on both wings and causing a reduction in lift cause by flap usage but allowing the steeper approach angle that flaps provide, especially useful in the L-1011 that was known to have poor visibility on approach and low flap settings
Your observation in the 777 is simple control surface design and operation. When a turn is commanded (Via Yoke or A/P) the appropriate aileron will move to the required position. However if the Rate of input of this command, or the desired angle of bank is grater then the authority of this aileron. (i e: It cannot be achieved with just the aileron). Then the spoilers (flight only) will deploy, this will cause a reduction in lift over that wing, causing a wing drop and as a result establishing a turn (through many other aerodynamic processes)
Your idea of a gust alleviation system is impractical and illogical, because at the speeds aircraft fly, by the time the system had recognised, combated and adapted to gust the aircraft would be out of the gust area and would have to alter itself back to the “neutral” position.
The actual upward deployment of the ailerons would more likely act like spoilers/speed brakes and either cause a descent, or aircraft buffet, or because of their aft position relative to the wing centreline cause some other aerodynamic instability
On an interesting side note aircraft are usually designed to withstand updrafts of 50 to 100 feet per second as per FAR 23 and FAR 25 requirements
Hope this helps