I love the idea of Webmention becoming part of core.

One of the benefits I've seen with it is that to comment on my site, you need to post it on your own site first to send me the notification. People are much less likely to publicly spam me when they have to host the spam for themselves and associate it with their identity directly. (I'll admit that this doesn't get rid of all spam, but it does help to significantly cut back on it. To date, I don't believe there's been any Webmention spam seen in the wild.) If anything I've actually seen more civil and substantive conversations from those using Webmention. It'd be interesting to see WP Tavern support it.

Reframing the design, UI, prevention of abuse, and set up of how comments are done on the web is certainly a laudable goal and one which could use some rebuilding from the ground up.