Don't pug something expecting perfection and you won't have any issues. If you want to control all variables, make a group. You can even put notes in a PF on what you're looking for and would be within your right to remove players who didn't follow those rules.

I have see it suggested to have EX primals and Savage stay available in RF. So long as they also were eventually added to DF as well to give a choice, I can't see a problem with that.

The problem with using SSS is what do you do about healers? Okay, you can test our dps capability, but there's no metric on how effectively we heal. And SSS does nothing for ability to handle mechanics. So dps isn't everything in those fights and SSS would not be a really good gauge since it can't factor in all the measurements.