There’s a lot of load in terms of PR reviews for core integrations, especially new ones, but end users can’t do much to help, nor is it easy to test an in-progress integration unless the author commits to maintaining an in-parallel HACS integration.
It’d be fantastic if there were a straightforward way for end users to test out in-progress core integrations (or enhancements to core integrations) without having to run a pre-release HA version or deal with copying source files from github into the filesystem manually.
While this may not speed up the code review itself, it seems like it would give the opportunity to help prioritize code reviews based on the number of users testing an integration and also increase confidence in the code quality of an initial release, as users could report bugs to the author before the integration makes it into core. Finally, if the original author abandons their efforts for any reason, the code itself would be in a better position for someone else to pick things up and take it over the finish line rather than languish partially (and potentially, never) finished.
Sample integrations that I’d have been interested in testing (and still using), but didn’t make it through a code review without going stale.
Add support for Hatch Rest noise machine and light by ViViDboarder · Pull Request #77381 · home-assistant/core · GitHub - Hatch Rest
Add config flow to Amcrest by flacjacket · Pull Request #80453 · home-assistant/core · GitHub - Config Flow for Amcrest
Add device triggers to Panasonic Viera by joostlek · Pull Request #98072 · home-assistant/core · GitHub - Enable ability to remotely turn on Panasonic Viera TVs (this was broken during the migration to config flow because it relies on WoL packets, and not an API call.)