How come no one complains about vayne anymore?

There are bigger issues right now. We have juggernauts to complain about and kog'maw. Fiora is the new vayne in top lane.

because people have figured out how to CC her hard

Because right now there are at least 10 picks that are twice as strong and kinda OP (in any Position, not limited to marksmen)

Vayne's actually fine. I have a problem when I play a tank, and I want to itemize so that Vayne deals less damage to me... and there is nothing but Randuin's Omen, which doesn't really help with the true pain. She isn't OP, but it is annoying when there is nothing you can do to lessen her damage output. As a tank, that's what you're trying to do, stop everyone from hurting you so that you can disrupt the enemy and allow your allies to deal damage. It's frustrating when you can't do that, but at the same time, it used to be worse. It really isn't that bad right now.