I would actually bet that emulating a PS4 would be easier compared to the PS3. You would be emulating x86_64 on top of x86_64 instead of PPC/Cell on top of x86_64.
That would be freaking awesome if it actually runs on a regular computer and not computer we'll have 5 years from now (as was the case for a lot of emulators when they started working on them)
I'd imagine any emulator would be serious about supporting core features of its default controller. Might take a bit though.
For what it's worth Yuzu (the Switch emulator) already supports gyro aiming with PS4/5/Steam/Switch Pro controllers natively and feels pretty great. I'm sure other emulators have made progress there (I recall Citra's 3DS gyro emulation working but feeling off)
What are some PS4 console locked games? I don't think there are many right? Most have made their way to PC already I think. I guess the only thing that really comes to mind for me is Gravity Rush 2.
Oh shit, you're right. That's the one everyone mentions too, for some reason in my mind I always think that was like a late PS3 title that was ported to PS4, but no you're so right. This would be pretty big for Bloodborne fans, hopefully with capabilities for higher framerates, and higher resolutions. Not to mention, maybe mod support later on in development? That would be dope. Watch, the day this gets published, Sony will announce a Bloodborne remaster, I just have a feeling.