Easily BLU. I think the BLU level cap and new spells is what I'm most excited about.

After that probably the relic, though I'm more meh on that than I would be with an Exploration Zone. New model and aura effects are cool, and I like the Hilde story enough I want to see the next part, but I'm not as excited as I would be, say, if we were talking about Pyros dropping.

After that, probably Criterion...but meh. I didn't do the last one at either the medium or hard difficulties, just the solo mode since I wanted to see all the paths and the story. But that's because I cared about Sil'Dah'/Ul'Dah's combined lore. I don't even think I've heard the name of this mountain before, so I don't actually care about it at all at the present time, and so I have no interest in the story going in, even if they give me some reason to care (maybe it hides a secret Allegan outpost with major lore implications...but probably not; it's not MSQ, after all.)

Don't tend to care about the Crafting/Gathering relics. I like some grind in my relics, but those are just MINDnumbing. I still haven't finished the Ishgard ones (though I've come close with one...like 2-4 years later...)