I don't want this lens. But then, why am I checking the current price on Amazon??
Actually, what I'd find useful is a comparison between the 100-400L at 400mm and the 70-300L at 300mm cropped to the 400mm FoV, on a FF body. Since getting a 600, I use my 100-400L less, but I do still use it. If it could be replaced by something smaller and lighter (70-200 II + TC need not apply!) without sacrificing IQ, I'd be quite interested in the 70-300L.
I don't have a 100-400, but I do have a 70-200 II + 2x and a 5DIII. If interested, I could take a few pics of items in the yard, maybe even a shed (although I promised not to underexposed by 3 stops and then lift it in post).