Dark bellow features hive enemies.. So solar shields and arc shields will be present (knights and wizards). So level the weapons with those attributes IMO. I think I read in the weekly update, but could have misinterpreted, but deej said something about revamping what you could buy with marks when the DLC hits, so could be new weapons, armour, anything! (Correct me if I did misinterpret that please!) As for who to rep farm? That ones all speculative, as no faction specifically has a "be all and end all armour/weapon" each faction plays to specific stats and player focuses.. So it's down to the individual!