I must be one of the "oldest skewl" people on this board, and I still climb WI-4 ice with straight shaft tools. I learned with them 20 years ago, and have used straight shaft tools ever since. I have no problems that hinder my climbing (other than I'm fatter now and this forces me to climb less hard lines). Once I bashed my knuckles a few times, I learned how not to bash them (much) anymore.
It's all a matter of good technique and what you learned with. I don't think, if I ran right out and bought a pair of swanky curved shaft tools, that I would climb any better than I do with my BDs right now. Of course, YMMV.