- COTH is awesome and can save so much time to get into weird places.
- Pet can also serve as a backup tank when the Paladin faceplants.
- Mage DPS is solid
I'd be more inclined to look at the viability of a Ranger in this group. Ranger can be one of the best dps classes - and in earlier game it was the absolute top DPS class - but it is also harder to automate. (It could be just me - cos my Ranger ini sucks.)
DPS is not required to beat every expansion (It just makes it easier) I would go with whatever you enjoy more.