Pure Int build or Light Armor build???

Purely for PvE, go pure arcane robe. Your pet is your tank, you shouldn't be taking hits in PvE outside of aoe attacks. A pure arcane build will kill faster while grinding with the higher magic attack, and have an easier time pet tanking with better heals. Given that non-heavy venos operate at range, most attacks you will be subjected to are magical anyway; you just need to be even more careful in watching out for adds or spawns behind you. Light armor is primarily for added survivability, flexibility in better utilizing both sides of the skilltree, and for spike damage with the higher crit rate, all of which factors more into PvP. Should you change your mind later on PvP, can always restat then, not very difficult.