@Riot:New Passive for Kalista's Rend?

For as much of a core part of her kit Rend is in doing damage, farming, laning and objective control I don't think it's interactive enough for the player. In the past it was nerfed to the point that using it as a means to poke/whittle down your opponents gradually was very inefficient, due to the mana refund costs being very harsh. This removed a very useful and skillful aspect to the champion that in it's present state makes it hard to lane as Kalista. Why not do to Kalistas rend similar to what you did to Cassiopea's E, by rewarding the player for using it correctly. At the present moment you arent really rewarded for it at all, but you are heavily punished if you mess up, long cool down and massive mana loss. True the potential upside is great, but perhaps you can tone down it's maximum potential to make it more interactive early on.

New Passive: Everytime you kill a unit/monster/champ with Rend you gain a temporary attack speed buff. For a "x" amount of seconds your next cast of rend will deal "x" bonus damage. Failing to execute rend on a unit/monster/champ will reduce rends damage by "x" for the next "x" seconds.

I think such a change will keep the skill cap and curve learning curve of Kalista high while giving power to her kit in a healthy way and allowing experienced users a way to be rewarded at all stages of the game for thier mastery of the skill and champion.