Wings, by removing the dihedral you would cut down the self-rightenig quality of the trainer. Basically you would have to put it in a bank and you have to take it out of the bank. Your trainer would tend to roll a little better. Now, by increasing the aileron surface you could be opening a pandoras box here. If your wing has been maximize for that amount of aileron area and you like to fly your bird considerably fast then by increasing the surface area you might create flutter unless you include some aerodynamically balancing. But yes, your rolling effectiveness will increase.