I'm linking this[0] post, not to talk about why/if neovim is better than vim, but rather because it gives a nice overview of why that patch was rejected, and why neovim was started.
Look at the linked mailing list thread. It wasn't rejected, there were several adjustments for coding conventions, naming, etc and the last thing Bram mentioned was basically "we'll consider it".
Then the developer threw a hissy fit a few days later and created a fork because his patch wasn't accepted right away.
> Then the developer threw a hissy fit a few days later and created a fork because his patch wasn't accepted right away.
According to the Geoff Greer, they didn't fork Vim. The fork happened a couple of months after their patch wasn't accepted, and they joined: "A couple of months after my disillusionment with Vim, Thiago de Arruda submitted a similar patch. It was likewise rejected. But unlike me, Thiago didn’t give up. He started NeoVim and created a Bountysource for it."
http://geoff.greer.fm/2015/01/15/why-neovim-is-better-than-v...
I remember when that went down and I was sympathetic. It was a shit show and a total waste of their time. I would have been angry enough to start a competing project too.
This would be a post hoc, ergo propter hoc fallacy:
1. async feature proposed and implemented in neovim
2. vim comes out with its own async feature.
shazow's post has significantly more evidence of neovim's responsibility, enough that it isn't a fallacious argument. It isn't definitive proof, either.
Did Bram Moolenaar tell you that? Otherwise, none of us know what motivated him.
Neovim fans seem to hijack Vim discussions frequently. Sometimes people want to talk about Vim.