i mean, i would absolutely get rid of the need to poo if i could. A significant amount of the mass in poo is just red blood cells, which you could surely engineer the body to just recycle. It seems to me that poo is almost entirely a symptom of unintelligent design.

Pee is a different matter because there are things we simply have to get rid of, and flushing them out with a bunch of water is a sensible way of doing that. Just tweak things so it doesn’t need to be so very dilute, and you have the ideal waste disposal method.