Thanks for the link to an interesting discussion. While I can't speak to the quality (or otherwise) of the vim code, I wouldn't characterize that conversation as "demanding" or "over the top". Even the most recent patch is reported to cause hangs when doing something as simple as pressing the leader key. You can't rationally expect a maintainer of mature software to sign up for that. I doubt Debian or other downstreams would be happy to hear that the vim maintainer had signed up for that.

If the fork is maintained for a year or so, fixing problems with the timer code and feeding patches for actual vim bugs back upstream, and adding tests for all of that, at the end of that time this patch will be quite different. It might even be in a form the vim maintainer can merge in good conscience. As an added benefit, by that time some compelling plugins that take advantage of these timers might be written. As it stands now, the use-case for this patch is rather hypothetical. Indeed, if after a year there aren't a few plugins around that make good use of this functionality, it calls this entire effort into question.