Overhauled macOS support; Save/load animation editor color palettes; Loads more.
Did you report the issue you faced while developing the Steam Overlay directly to Valve with the exact feature/enhancements you would need for better Steam Overlay support ?
I think the best would be to report it yourself (as you know exactly what is lacking currently) and post it publicly somewhere so we could all +1 your post and comment your request.
I can't find anywhere to publicly report it. I've repeatedly tried to report it to them privately, and they either say it's supported and should work, or that there are workarounds (which don't actually work), and then they stop responding to further messages. I think the only thing that will persuade them is if lots of people get in touch with them and ask them about it.