You're better off sticking with shield for survivability and then focusing on the "open" skills, ground spikes are priority #1 and then either spikewave or uproot depending on the makeup of the game. Ie: against a rook on crucibel you'd be better off with spikewave since it will hit a few of his towers + him + creeps. In a small or wide open area game uproot is often better.
Ignoring the closed skills other than shield is imo the best way to go. I play QoT almost exclusively and if you check ranking you'll see I win most of my games. If you don't agree, at least do me a favor and do not get shamblers against oak, it just is giving him free hitpoints.