(B) You are free to run ANY as you like on your domain. For domains you own, this RFC doesn't change anything.
(C) Would you advocate for responding to AXFR / zone transfers? There generally is consensus that allowing enumeration is not desired.
Since most servers are web servers these days, you can get pretty close to this goal from certificate transparency logs.
This was proposed solution, the problem is that in case of attack, against a valid Authoritative service, launched via open resolvers, the open resolvers would just download Gigabits of ANY traffic with TCP. Read about this here: https://fanf.livejournal.com/140566.html
None of your business, really.
> Combined with GDPR killing off whois the internet is a much more boring, less transparent place.
Thank lord for that, there's literally no benefit from it, with WHOIS evil still did evil and normal users got their privacy violated, without WHOIS evil can still do evil and normal users' privacy is protected.
Cloudflare's argument's are all based around ANY making it slightly harder for them to make a profit. A small chance of DNS amplification attacks in DNS is what Cloudflare thinks about because it's their business. But there's no reason to believe this is more important than individual users wishing to see what servers are behind a domain.
Combined with GDPR killing off whois the internet is a much more boring, less transparent place.