One question I would have would be: What will the revenue be spent on?
Around 2006 or so (give or take a couple of years), per some stories I've read the SEC was taking in about $600 million in fees, annually. That went to Congress (effectively, when comparing influence to the Executive's, in this matter). Who in return doled out a budget to the SEC of $100 million.
I think transactions should be taxed, in good part (but not entirely) to pay for the obviously needed oversight and regulation. But if you fail to do that... you're just heaping distortion upon distortion. You're still failing to address the underlying problem.