100% agree, the most satisfying moments of the game happened when you were leading enemies on a big chase, and watching the ball blow them up.
Not much risk of getting hit by the ball I admit, but maybe it would have been even cooler to just embrace the fun of that mechanic, and do away with the self damage entirely. Different concept in the end though for sure, that would probably look more like an arcade game in the Geometry Wars style, or something similar.