Peter Marsh wrote:
Couldn't be more than a week's work. Let's see if Apple take the ball and run with it. They invest millions in developing features that I'll never use. A few thousand on this one and I bet thousands will be thankful for it.
You were already provided with the direct-to-Apple feedback link: Feedback - macOS - Apple
Feedback in Apple Discussions goes to other users, not to Apple. Apple has some moderators keep an eye on content here to remove posts that violate Apple's rules, but there is no feedback path in Apple Discussions to Apple Engineering.
As for taking one week's work -- I don't know if you have ever worked on large software products with a large user base, but I think you are vastly underestimating the amount of effort needed. After changes to the macOS, there has to be a "soak" period with extensive testing to follow, on an array of platforms that Apple still supports, and in this case there is a hardware aspect to it as well.
You mention "dual monitor" setups, but some users make use of three monitors (or more). Are you proposing a separate mouse for each monitor? Do you see how complex this can get? Also, the situation with a laptop plus one or two external displays may be different, as the laptop has its trackpad as well, which is its built in "mouse." But it is different in some ways than a mouse.
I think the vast majority of iMac users utilize that single display that comes with their iMacs. I have never heard of this request ever, before. How many users would really use this "feature?" I wonder what the demand really is for this. At my employer, where several thousand scientists and engineers are using Macs, I have never seen such a request, not once even. Some of them have vast extents of external display real estate in use.
Use the Apple feedback link. If there is demand for this, Apple might consider it, but I sort of doubt that the requisite demand is there.
Neither Windows nor macOS supports this natively. I believe there is a Windows app called MouseMux that does something like what you want, although I believe it was oriented towards multiple users, each with their own cursor. Because Windows does not support this natively, there have been reports of glitches or conflicts on Windows machines where this is being used.