Personally I would play them as you have them.

Affliction warlock and resto druid.

I would have the resto only there to pop heals on the warlock. The lock would be drain tanking 3 - 4 mobs at a time.. and the druid would pop a heal on the warlock if needed. It might be that the healing could mean the warlock could pick up more mobs to drain tank, so upping your damage.

I soloed a lock and Pre 60 with no spell damage I was drain tanking 3-4 mobs no problem, and with no breaks between pulls. Outlands was a different matter entirely... I switched to felguard.

If you are happy with that then don't worry about respeccing to moonkin.