The makers of Silentium, a content-blocking app for iOS 9 have an interesting, if overly optimistic point of view on whitelisting:
We will try to set the example by including some sites in the white list by default and we will also make adding sites to the white list as simple as possible, by providing a Safari extension to do so without ever leaving your browser.
I think it's good that they're thinking about the good publishers. I think it's great that they're making a Safari extension to whitelist sites with ease. Unfortunately I think they're overly optimistic. I don't think many people will opt-in to ads once turning them off, even on sites they love.