This is one of the two builds i use for valla. I discovered if you're moving in a pack of at least 3 or more. There is a high chance you can protect and annihilate anyone stupid enough to try and step near you. Tanks like Diablo and the lich king are good to have around. Other heroes that work well with this build are Kerrigan (pull and stun), Uther (heals and stuns), Zeratul (Slow and High dps), and Thrall (he's basically a weird version of Earthshaker). Honestly if you have a good team (or people that at least know who they're playing). There is no danger to you.