I honestly think we're all over thinking this. Imagine you're a small business owner trying to build a business without running out of money ( which Mooney has now done twice). If you could build a rudder that needed the same tooling and manufacturing processes as the elevator with only modest diminution in performance and could produce a distinctive profile to boot, what would you do? That is what, I believe, Mr. Mooney did. Modest diminution in performance is probably something I'll be challenged on, but the trade off in what he did, it seems to me, is accepting an elevator that has a symmetrical cross section. I THINK that requires a greater angle of attack to produce the needed lift. But it saved money.
I love my Mooney but think a few compromises were made. I don't blame Al.