Gems: not an expert to say
Bow > full gear. Even after getting an ayanad full resilience chest piece, I hardly feel tankier than before. It's all about avoiding dmg and dosing your opponent. I've been in divine T4/aurora for years now, and compete, not to mention best, ppl in full epic sets of T5+ armor, with a leg costume full of dmg stats, and a leg T7 bow, and only 85/300 points into my migration path-agility, if that helps you decide what to focus on.