If a wing can change its incidence angle, can aileron be omitted in the design?
Since aileron are used to increase lift and decrease it. so is the incidence angle.
How would the two solutions compare?
So did the Wrights in their 'Flyer'. It had no ailerons, but the wings could be slightly deformed to roll the plane.
Possibly for constructive reasons, ailerons are almost always used today for roll control (spoilers are sometimes used in very light planes) but the Wrights' method was more elegant...
In principle, yes.
But, what would be the result of it?
Modern aircraft wings are a result of sophisticated design. They could consist of the following parts: Flaps, slats, spoilers, pylons, fuel tanks, winglets (of course the ailerons) and some also hold the engines. If the entire wing is to be moved, all of these parts would need to be moved too, or else, engineers will have to come up with a complex design that could keep some of them stationary. Each of these parts have their own function. Would they operate the same way if the wings moved? Maybe not.
Moreover, the amount of aileron deflection required to create a change in drag at a higher altitude is much lower than that required at a lower altitude for the same amount of drag. Such fine control is hard to achieve if the entire wing is moved.
Some radio control gliders use wings that can change pitch angle independently. "Wingeron" models, use the wings for roll control, but have a conventional elevator. "Pitcheron" models use the wings for pitch and roll control and have a fixed horizontal stabilizer instead of an elevator. A "computer" transmitter is used on "pitcheron" models to mix roll and pitch control inputs into servo position output commands (also used to reduce or eliminate any adverse yaw issues). These type of models tend to be aerobatic oriented, and weigh more than conventional model gliders, as the lighter models would have a smaller sink rate.