Mandrake Ward more important then we realize.
The biggest thing about this PBE patch in my opinion is the Mandrake Ward. Since it works against invisible units it will allow riot to include half decent stealth champions in the game again with out absolutely breaking them or making their game-play counter-intuitive as all get out (I'm going to "sneak" up on you and assassinate you, have a giant exclamation mark so you can tell I'm nearby). Champs like pre-rework Eve and Rengar would never have grown to the heights of power they where at if Mandrake ward was in the game at those times, especially considering its a stealth ward so you can drop in your lane to detect ganks coming up the lane from the enemy tower as well.
I hope this ward makes into the game, and further more I hope it marks the return of "Stealth and Stalk" champions now that counter play would be so readily available.