I agree 100%. I don't like the new Elite mileage policy, and I think it could have been handled in a much more positive way (a la AA), but I can't argue that it's unfair.
I have occasionally paid a little extra to get an upgradeable K fare, but I'm not about to pay $400 extra for a K fare (or an H fare to Hawaii) for a chance to upgrade, and I certainly won't pay Y for my leisure travel. I'll just take my business somewhere else when I want an upgrade.
BTW, I know the 50% mileage accumulation applies on partner airlines, but the new upgrade policy doesn't, does it? If not, NW will be getting our international business from now on. As much as I enjoy BF, it's not worth THAT much.