I feel this tree ignores the fundamental problem with Guardian Druid - the lack of magic mitigation. After all, this tree only provides 6% Arcane damage reduction (helping only against literal Mages) and 3% magic damage reduction overall.
This tree, much like the Wilderstalker tree, leaves the question of what changes are going to happen to the main Class Tree, which is poorly in need of a revamp.
I offer Kakaroot’s post regarding the Druid Class Tree being downright awful
Aside from that, Lunar Beam is minimally taken by Guardian Druids at present. I’m noticing these Hero Class trees forcing off-meta selections in the current Class and Spec trees to accommodate them - without any indication that the existing trees are even being adjusted in any way.