First when I read the tittle, I was thinking, no way! No ads on Steemit.
Just yesterday I wrote couple of words about how Steemit changed my perception on ads, and that I'm finding them more irritating now on other sites.
But reading your proposition about the possibility of settings, and does the user want ads, and putting threshold limits, than maybe is OK.
Users can still chose do they want ads or not. If this option is available for FREE, than having the option is a plus and addition to the system.