But it's not human readable anymore, nor backwards compatible. The expectation was that the industry is reasonable, but it proved to be as hard as it would be to push breaking email v2 implementation.
As a human, I've found that e.g. "fd00::53" is perfectly readable to me, and most of the time you're interacting with strings like "news.ycombinator.com" anyway which is identical to how it works in v4, so I'm not sure how far I'd agree with that part either.