This move was: VERY LATE MOVE
I guess they would do better if they would give publishers the right tools to filter/approve advertisers. For whatever (wrong) reason they are just giving tools to advertisers but no tools for publishers.
If we had these tools available all these spammers would already be out of business because most publishers would filter them.
How can one filter per account with 200 domains limit can work for larger publishers? (or any publisher) I have 7 larger websites and this filter does not even hold all the MFA for one site.
Just give advertisers the tools to pick and choose and give the same tools to publishers and you will have natural and healthy network.
Advertisers will pick high quality websites and publishers would approve high quality ads. Very Simple.