It might not be for everyone of course, but I feel a bit of bubbling in my belly when I keep seeing people say "it's almost the same as the 70-200 @ 200" no it is not. It might not be worth it to you, but it's a BIG difference. I must've read a thousand user reviews that said the same and 90% had one thing in common, they were written by people who had read other user revies, not by people owning or using the lens.
The 85 L is wonderful for some things, but "sharpness to die for" when we're talking about the 200 f2? Yeah, not so much.
And I think what makes a lens give that pop, is very high level of sharpness against the smoothest possible background and there there is no lens like the 200, unless you go even higher up. But for portraits I find 200 is the longest you should go for head shots.
Again, it isn't for everyone and god knows it's a lot of money, so if you're happy with the 70-200, there's nothing wrong about that, because it's absolutely killer and one of the best zooms ever made. But it's never going to be "basically the same as the 200".