I am low vision. The mouse cursor is a critical and precise input device. The most obvious thing you could imagine doing with it for low vision people would be to make it bigger. This is such a no-brainer. I can't imagine a good argument against this solution.
Windows, which I no longer use, handles this exceedingly well. Not only can you choose a large or an extra large cursor but you can also change the color, shape and add a tail. For me, with one eye, it really helps my one eye to track the cursor when it has an adjustable tail.
Yet, in Ubuntu, since Dapper Drake, I have never seen a setting to change the cursor size. I just ran a program which I downloaded from linux.softpedia.org called "whitelarge" which involved used gconf-editor. All the procedures ran smoothly but no change. I also tried "big-cursor" which I loaded from Synaptic. That failed. I also tried two editings from gconf-editor and dconf-editor. They failed.