It is all to the good, even if long delayed, that fewer firms will be subject to the Form PF filing requirement, and for the firms that are still subject to the requirement, it will be made less burdensome. The real question is not whether it is ok to make the eliminations and modifications suggested by the Commissions; the real question is whether Form PF, in its slimmed down state, will continue to be more trouble than it is worth.  

CAT is the exemplification of a regulatory mind-set, now—at last—being challenged, that there should be no limit to the amount of information that the government should be able to collect, without regard for any of (i) the costs of collecting and maintaining the information, (ii) the value of the information (other than the fines that can be collected for failing to provide it), and (iii) the danger of aggregating so much information where it would be an incredible target for hackers.

Monitoring insider trading in prediction markets is going to be a very tough task given the breadth of possible contracts and the diversity of individuals who could have access to inside information.

The question is generally not whether a rule changes any benefits buy-side or sell-side; both sides include numerous sophisticated entities. The question is whether any particular rule change is good for the markets; that is why so often buy-side and sell-side were agreed in opposition to many of the proposals put forward by the SEC under the prior administration.