Power is torque x speed, you can trade one for the other but torque is no criteria of power out. Yes the motor will increase load with speed, but just providing torque will rob you of the speed component and you are no better off.

If you put bigger than 4ft blades on that thing you will burn it out anyway unless you have some furling or control scheme. You can use bigger blades with speed increase to get more power in light wind but it would be pointless to go to the loe speed high torque blades with high tower loading and low efficiency just to avoid furling or some form of current limiting.