Yoshi has referred to us, in the future, getting hybrid jobs. The idea is that in a full party, you will have 2 of each job type: 2 tanks, 2 healers, 2 DPS and 2 of this hybrid role. Most likely it will be a support type.

Personally I could see the following as support: THF with Trick Attack, doing damage bursts from behind tanks to spike hate; RDM that does AOE enfeebles; BST that can tame trash mobs and turn them on other mobs, using their own skills against them, including mobs that buff, giving group buffs to the party.

Unlike unlocking jobs in the current system, it wouldn't surprise me if unlocking hybrid jobs required level 50 in one job and level 30 in another.