I did a similar build to what totallymady is suggesting. Nature's Grasp to stop them from coming too close too fast and ganging up on you, Steady Shot to double my chance for crits and increase firepower a lot, max Focused Mind, Blinkstep, Mind Race (casting speed affects Steady Shot), Malicious Intent, Killing Spree (assassin tree), Sylvan Touch (prefer it to Refresh. however, taking Sylvan Touch also means I have to take one point in Wizard's Spirit, but that's okay and worth it) Recall, enough Spirit of the Grove to get Blessing of the Wind, then the rest into Spirit of the Grove. I experimented with Dead Eye and Stalker's Spirit, but Spirit of the Grove wins out by far in the end. You get +1% crit for about 4 out of 5 points in SotG, and the damage bonus to bow auto-attack is about as large as you would get with Stalker's Spirit.
Pretty fun game.
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