The intention is to try to inch in the direction of a more self-regulating community while improving the quality of the discussions. Improved discussion quality is by far the most important thing and as far as I can tell this experiment is a big success in that department, so the essence of the HN is definitely not being diluted by it. If it were, we'd stop it immediately.
Not sure if that helps or not!
Edit: if anyone wants to see a typical example, here's a top subthread that one of the users we're talking about correctly marked as offtopic: https://news.ycombinator.com/item?id=31231858. That's the kind of pointless flamewar stuff that tends to get stuck at the top of a page. Downweighting it makes everything better, and having more eyeballs out there to catch it sooner is super helpful. That's the intention behind this experiment.
This is the first time I've seen something like this on HN though, so if anything it might show how good the HN policies normally are. I just wasn't aware that some members of the community are more equal than others; now that it is clear and communicated, I can make better decisions myself.