The real benefit of Lone Wolf is in the extra ability points it grants. Extra AP is OK, extra HP is good. However, at level 20, you'll have 20 extra ability points to spend, that's enough to max out one extra ability and take another one to level 2. And that's without having to sacrifice talent points and such.
Taking two Lone Wolves may be a problem because you'll have to spend at least some points in crafting (without crafting, you close some major income avenues to yourself at least). One LW plus one regular character lets you have a slave monkey for crafting, and a competent third for fighting. If all three characters take Witchcraft 3, you can summon three Armored Decapitators (INT does not matter for summons). Take Farsight and keep it up at all times so you can get the drop on most enemies. Summon the Decapitators close to your enemies and let them take the alpha strike. Then move in and go nuts with AoE. In my experience, the Decapitators are scary enough that they hold aggro as long as they are alive (even if they are frozen or knocked down). For more versatility, learn other summons in case the enemy happens to be weak vs. an element. If the summons die and you need a break, go invisible for a few turns (Walk in Shadows, Invisibility), wait for the summons to come off the cooldown, rinse and repeat. You'll never miss the fourth character.
