What’s the one thing you wish your phone has that your camera doesn’t? For me it would be quality of the screen on the back followed by weight.
Is the question what property exclusive to the smartphone I would like on my camera, or vice versa?
In the former case, I wish modern ILC would embrace computational photography more. In particular all kinds of it that relate to combining a series of pictures into a single image to enhance detail and noise, as well as those aspects that allow manipulating the image based on depth maps, such as blurring a background after the fact or adjusting the lighting separately for the foreground and background.
That is the sort of technology that is employed heavily in smartphones to allow them to come close to what a dedicated camera produces on first glance. And fundamentally it is technology that allows inferior hardware to produce good results. Which of course isn't really what ILC manufacturers want to provide us - they are more into selling superior hardware to improve the quality.
As for the phone, I don't use it to take pictures at all, basically. Because it lacks one key feature: Enjoyable ergonomics. I do photography purely as a hobby and touching a section of a screen does absolutely nothing for me emotionally. The interaction with the image is so far detached that I am not getting anything from it. No wheels to quickly change settings or AF point, no swivel screen to see a preview of my image without getting into uncomfortable poses, no decent grip to get a sense of stability and control, no means to manipulate the flash...
But addressing any of it really would diminish the qualities of smartphone I and the market as a whole value.
It is mind-boggling how far compact hardware has come, but for all use cases where compactness is not the primary concern, you will always be able to deliver a superior product by prioritizing the primary qualities the customer is looking for. Be that ergonomics in the case of office work places, computational power for serious tasks or ergonomics, flexibility and optical quality in the case of cameras.
But, for any given use case, a user of course has to evaluate how much their use case warrants compromising on the intriguing quality of compactness a smartphone provides in favor of a dedicated device.