Actually multiple people have complained, some less hyperbolically than this author. And, unless you think the people who build their own Emacs from head of master are less likely to use more obscure features of Emacs, then this feedback was always going to come before anything that actually hurts the Emacs community made it even close to a release.
Having read/skimmed the bug I see now that the issues objected to by Eschel were all raised early, back in October, by the other developer looking at the work, Michael H. He pointed out the RET thing and the issue with using control characters as a registers.
