OK OK I get it Andy and I know what you say but please first do not show off your young age and young good eyes...
Then the problem with macro and manual lens is when you stop down maximally for best DOF, screen is almost completely dark, not like short range tele lens. If you do a prefocusing at wide open f stop, then back to closed diaphragm, you can almost say good bye to you nice impatient insect or water ever other living small being is in front of lens.
Additionally I used to feel like what you said on manual area, but find it quit difficult to focus rightly with DSLR. And no it is not picture taking that is difficult, its when you check the images on monitor later that you see how surprising great number of them are out of focus.
To alleviate this I got 2x viewfinder magnifier, both Nikon and Olympus. Non with much success and the Nikon version is a total lost IMO.