My sister asked me to look at a fan that had a death wobble. Turned out my neice was throwing shoes at the fan and bent one blade at an increased angle.
I took all the blades off the fan, welded two bolts to a peice of steel, clamped it to the workbench, attached the blades and used an angle finder to adjust the blades until they were all at the same angle again. Was really easy to be honest. Tested the fan with me sanding directly under it so if something flew off it wouldn't hit me atleast..... It has been in use over a year and has had no issues.
I would think you could do this to increase the angle, but do not know how much angle you could add before affecting the motor or strength of the blade. One the model I was working on it was not an issue since I was returning it to the factory angle, and the blades were vastly strong enough to have had their angle inceased anyway. I would think there is a chance you could burn out the motor this way, but if it did, it would be a good reason to change out the fan anyway.
I make no guarantees that thing will work, but it might. Just my .02