LANE SUBSTAIN STUN.

First few levels you want to dedicate your skills to keeping mana and lane sustain. The other talents do sound appealing but your goal is not damage your goal is to stay in the battle as long as possible. Let the Valla do the damage. YOU DO THAT BY STUNNING AND staying out of combat for 5 seconds.

LEVEL 13 you can go any of those this is the one that is truly Situational. I think I will pick rewind the most tho so I can stun more 40% and the healing static 30% and the rest like 20 % this level really is a toss up for me.

LEVEL 17 MORE STUN.

LEVEL 20 blink or his buff ultimate. BLINK SO SO BROKEN WITH ANY HERO