I don't think it's a killer app problem so much as a general UX issue. I really love RE4, I've played it 100x on the GC and Wii, I could play it in my sleep.
I got it on VR and it was awesome. It was so much more intense and fucking cool and extra flexible (I can hold a knife and a shotgun at the same time???? fucking amazing).
The main thing is that I don't want to just play video games. I like to jump around a bit and do other things. Switching apps is just really annoying in VR, usually it's not even possible.
Probably a better example is Netflix. I usually have TV shows on throughout the day, pausing them constantly for seconds, minutes, or hours, as I do something else, or often letting them play in the background. Can't do that on my Quest 2, it's either "sit in front of a TV and do nothing else" or don't.
To me, these issues are really more OS level/ platform level. The VR UX is out of whack with how I want to use it. Individually though, I can say that my experience is that a VR version of something can be way cooler.
Also, I'd like to have a keyboard interface. If I could wear something like fingerless gloves + have a keyboard hooked up and I just sit at my desk with N virtual monitors that would be amazing. But again, that's not really an "app" problem, it's the OS/platform/UX.