I hope so. There's certainly a lot of room for additional dungeons after all. From a PvE point of view I really like TWT - the first two fights have been very cool. I love the design of them too - they've really done the FF6 versions justice. In terms of their lore FFXIV specific, it's interesting - I just hope there's more to the payoff than a straight up FF6 reference.
I have a feeling Azyz Lla might see a lot of attention in 3.5 though. Perhaps we'll even get a Fractal (Hard) or Aetherochemical (Hard) in addition to the next TWT fight.
