If you have a DRK and WAR as your tanks, is it generally more optimal for the DRK to pull or for the WAR to pull? It probably varies from fight to fight, but I'm wondering which is "better" for overall group optimization in terms of DPS and hate-generation.

WAR pulling is ideal for not only DPS but overall threat generation. BB is unrivaled in this aspect and taking advantage of its ridiculous threat whenever you can is ideal. A DRK provoking off of a WAR is a much larger threat gain than a WAR provoking off of a DRK. This gives DRKs a large enough threat lead to remain stable against high threat generating jobs and require fewer (if any) Grit Power Slashes.
Threat is a resource. WAR's unchained opener is a boon for the party that lasts for the remainder of uptime.