Trident, as much as I think the standard plunger pump is barely adequate for use, you are perfectly correct. The first thing I do with a Triumph when I get a one is give it a heart transplant, in with the rotary, but if I pass it on to a new owner the original pump goes straight back on. It is too much risk that the new owner will forget to prime the pump when he changes the oil and will destroy the engine.I bought mine cos I was doing medium high speed sustained runs/touring where I would sit on 70 to 80 mph for 8 to 12 hours only [quickly] stopping for fuel.
But for a casual user [where priming could be an issue with the rotary] the plunger pump is much better IMO.
The 20% extra oil flow morgo plunger pump, seems a good compromise.