The odd-eighth spread pricing scandal was also something that was hidden from public view for decades, and it had a far more profound impact on the fairness of the markets!
Unless you can say that the "price extracted" is fair and self regulating without any clear and transparent oversight, I think there is probably room for improvement and a benefit from increased scrutiny. However, as I said, my knowledge of the internal workings of the markets is still pretty limited.
If you understand the scandal, you understand the answer to that question: automated trading, opaque as it is, strangled the spreads that human market makers had been capitalizing on.
