Yoshi-P mentioned some time ago that SE might look at adding jobs that are not traditionally included in final fantasy games.

With this in mind, and with a certain recently-released-in-the-west MMO having already broken the taboo of carbon copying Gunlance out of Monster Hunter, I think it would be cool to get Gunlancer as the next tank. We're sorely lacking in defense-themed tank classes (aside from paladin they are all "I'll brace the impact with my exposed vitals" style) and Gunlance's massive shield would level that out nicely. Of course, we're not due for a new tank class just yet anyway (next xpac will likely be two DPS: ranged physical + ranged magic).

I've gone over the character limit on my rotation design but I've already spent the time writing it so I'll split it up into comments.