Earlier quoted context omitted.
> He literally writes "people introduced new ``AAAA records'' into the DNS protocol, creating several unnecessary complications in DNS software." He says, right there, that AAAA records are an "unnecessary complication". To say that he wouldn't mind them is in direct contradiction to what he wrote. Sure, you can keep attacking the implementation detail here which he may or may not have overlooked. I would rather stee…
> DNS client that's new enough would use AAAA-only, if present, and ignore A. As implemented today, there's no way for a server to "force" the client to use AAAA and treat A as legacy. This is exactly how Happy Eyeballs works: request AAAA and A, and use AAAA if it returns. Trying to force things one way or another is a recipe for a bad user experience.
The intent with Happy Eyeballs was to focus on user experience: give IPv6 a slight initial advantage to hopefully only make only an IPv6 connection for the dual stack and not waste the network resources and CGNs bindings.
But at the same time, a short time after the start of the IPv6 connection, the IPv4 connection would also be initiated. Whichever connection wins, tilts the balance towards that address family for the next attempts.
This way the users on a broken or very slow IPv6 with fast IPv4 can still have a good experience, Internet Holy Wars notwithstanding.
Source: I am one of the two coauthors of the RFC6555.