What is missing is the ability to use each on an array.

I personally believe that it could be worth to remind of ysth's 5.12 feature quest to which I've just added a reply.

There is discussion about how to retro-future-fit it into the 5.10 maintenance track, so as to avoid a full release cycle that would require waiting for the first 5.12 release.

But wouldn't the new feature mechanism make it easier to implement new syntactic features without risking too much with backwards compatibility?