Let's all take a moment to forget about assassins.

{quoted}

BUT now it will be easier to itemize against her because a youmuu or serrated rush will also not destroy you so early... her big powerspike at 6 if she gets good CS is kind of out the window or at least nerfed.

Riven rushes cleaver, a smart one will at least in my opinion. Rushing ghost blade leaves you a little too squishy for the mid game. Cleaver also gives more CDR and a set of pretty amazing passives.

Flat armor pen is pretty unnecessary on her from the start. You could and can still kill squishes just as fast with Cleaver and Hydra.

Now with AP lanes you can go Maw into cleaver with merc treads and get max CDR without ghost blade being needed, it sounds pretty great!