Physical PS1 BC will never happen, PS4 conveniently doesn't support the CD format. (look it up) There are about 150 PS2 games that are on CD, so you can forget that too. Digital maybe (but unlikely), but not physical.
The closest I've ever come to using PSNow is remote play on my Vita. I never even bothered with PSNow when they offered free trials, but then I actually still have my PS2 and PS3 (and PS1, by proxy).
As for what I'd want in the next big FW update.......I don't know. That universal downsampling for 1080p displays sounds good.
Personally, I won't bother with beta firmware. Sony won't cover you if it bricks your console. I'm 100% digital this gen, not gonna risk it.