They're real power lies in giving them a Talisman accessory, and the Asaya staff. the Asaya is air affinity, so it is advisable to train your Channeler as such. Given that combination of equipment, as well as an armour that boosts spell range, turns them into one of the strongest units the game has to offer. As both the staff and talisman raise magical damage, they are easily able to kill any unit in one or two basic level spells. the spell that makes them broken though is they're Combo attacks. They have short range and draw off Affinity, but deal insane damage, easily dealing upwards of 1000 damage with a Combo 1 & 2.