The staff on its own doesn't have quite enough punch, but when you add the extra damage from a frost ring and a fire ring for that +2 damage, you start to get worthwhile damage. The real benefit you get from the damage is that it ignores armour. So if someone is throwing full plate mail troops at you - get something to tank for you while your staff troops shred them to pieces.
good traits are:
accuracy, to make sure everything hits,
spell resistance, if an ai is throwing spells at you,
dodge bonus id the ai has a lot of archer and it can help against melee in a pinch, it can be worth sacrificing 1 initiative and 1 hp per troop to gain +20 dodge, then with the robe for +10 more dodge that gives you 30 dodge in total - but then you need a lot of crystal for these troops and that can get pricy - so you want to protect them - enchant them with evade spell for even more dodge, and use obscuring mist spell and the spell that protects from range, and also the precog belt.
add some tanky units, not go kill.
edit: Heart of flame enchant to a city helps a lot too.
initiave > defence> health boost enchantment.