I never played XI, but lets take a look at what the Devs envisioned for FFXIV,
Look at the lighting, the shading the architecture, the real time water reflections. What happened, sure don't get me wrong FFXIV looks amazing, I max the game out, but should the cost of resources it requires to run at the highest quality be justified for what we have currently? I think not, a game like blade and soul has better shading and lighting, sure it may have lower texture quality, but look at how nice it looks blade and soul looks as is. When you are using Unreal Engine 3 you also get fantastic lighting realtime water effects amazing shading detail rich character detail, no load zones so you can steam content. All at very low resources on your hardware. Crystal tool may have potential, but currently the only potential I have seen is the character detail, and sometimes with the clipping errors, and lack of more realistic cloth physics that is bogged down.
Don't get me wrong I love playing FFXIV, I just think they could have optimized more visually for currently high level hardware than what we currently have. Low detailed water, lighting that reminds me of more unreal 2.x, load zones, shadows that eat up any high end hardware.