Agreed to some extent, though not really sure the protocol matters here... As an alternative, limiting IFrame to 1-3 layers would do a LOT in terms of reducing the overhead/bloat/risk... you get a full ad network payload, that injects an iframe because of a buy miss, then another, another, etc and so on.

In the end, limiting IFrame depth would probably do more than many things for stopping some of the bad actors.

I use uBlock Origin and EFF Privacy Badger for most surfing, which does a decent enough job. I don't think that the enhancements to the protocol really do that much... though I also don't know that some of the tradeoffs are worth losing a human-readable protocol.