That would be great to see and would solve a real issue for many users of services like ours (or Heroku, GitHub pages, etc, etc, etc).
There are gotchas however, since you now depend on two levels of DNS based traffic direction and we have sometimes run into issues where DNS providers offering ALIAS records simply cached one DNS respond and sent all DNS lookups to the same CDN pop regardless of their location :/
Could you explain more about what Cloudflare/DNSimple are doing to workaround this, from a technical standpoint?
It's explained in the article, but the TL;DR is that CF and DNSimple are simple pretending that a CNAME on the root domain is the corresponding A or AAAA record instead.
It breaks geographical CDN a bit but it works somewhat.
What Cloudflare and DNSimple are doing is the right thing. I hope that CNAME flattening or ALIAS records become some kind of standard.