Let's be honest, the Diadem flopped. It is a half-baked piece of content that isn't really serving a purpose at the moment. But, can it be saved? is there still time to fix the Diadem and have it be the piece of dynamic contact that we deserve? I think so.
So first, let's talk about the 3.2 changes that are coming that will give the Diadem new life, mainly the ability to supply Grade V Materia. It's no doubt that more people will be drawn to the Diadem due to the ease of obtaining rarer materias, but that doesn't -fix- the Diadem. The problem with the Diadem is the gameplay, not so much the rewards. By increasing the rewards, but not solving the gameplay issue, all the Devs are going to accomplish is upsetting the player base because they'll be forced into this mind numbing grind fest.
So while the Diadem will become far more populated once 3.2 hits, will we be having fun while we're in it? This is the question that the Devs should really be concerned about. Because right now, the Diadem isn't fun, and it's not something that people actively want to do. This has to be solved, and I think the answer is staring the Devs right in the face.
What is keeping the islands afloat? A giant crystal of aether. Who always seems to be in need of aether? The tempered Beast Tribe Clans. Why do they need this aether? To summon their Primal (Eikon, Aether manifestation, whatever you want to call it). So wouldn't it make sense that the various Beast Tribes would try to seize the Diadem for themselves, so that they could supply their god with an immense amount of energy? Not to mention, weren't the devs throwing around the idea of 'Wondering Primals' back during 2.0?
I think the Diadem is the perfect place to implement the Devs original idea of Roaming Primals. Imagine, each of the various Beast Tribes are located on a different island, and each of them are varying for the giant crystal in the center, to harness its power for themselves.
It could work like this: Each time you queue into the Diadem, you are set on a timer (45 minutes is the next maximum that is being introduced in 3.2 I believe). Maybe each time you zone into the Diadem, your group has to decide what it would like to accomplish. You could choose from killing mobs as normal, gathering, or hunting down a primal.
It could work like this: maybe the beastmen need some sort of an item or crystal before they are able to summon their primal. These crystals are held by different beast tribes or NMs, they're basically pop-items. Once you have the pop item, you can give it to the beast tribes, or whatever, and that unleashes the primal. With the primal unleashed, the players could then challenge it in the open area. I imagine it working like a FATE, and the group to do the most damage to it, would be rewarded with a special chest with a summoning stone in it. Using this stone would then summon the primal in the Diadem only, to aid the player's group. This would then satisfy the original plan for roaming primals that was discussed since even before 2.0 came out.
What it comes down to is this, the Diadem is boring. It needs something to make it "Fun", whatever that may be. This was simply a random thought I had that I wanted to share.