(Caveat: I’m not on any of the teams that have a say in this, just an interested community member.)
I’d say that, if you have a compelling enough use case, it will definitely on the table. Prioritization will depend on how compelling your use case is, though I probably wouldn’t hold my breath. As with anything, there will be a cost-benefit analysis and unless you bringing your own compiler engineering force, your idea will be competing against a great many interesting others.
That said, I think you should still write some version of your Rust 2019 blog post – I, at least, will be interested to read it!