If you remove the oil & keep the pump running you'll seize it.... you're eliminating the lubrication it needs on the pump end to run.
If you were to do what you're saying, you'd need to run a loop so the pump is always running oil through it. By doing this you're increasing risk rather than decreasing imo, which is the primary reason to go to premix.
What is your main motivation in making the change?
(I've run premix the last 18000 or so miles on my sleds, so this isn't a trick question, I'm just curious what motivates YOU to want to do it?)