Meh. I think SE went a little too far in tying everything about Eorzea back to the Ancients. Couldn't there have been some mysteries in the world independent of them?
I disagree with this. They never felt like a huge point to me. Some would get mentioned in passing as patron deity of this or that city state or guild but little more. Halone was the one exception as patron of Ishgard and important to Ishgard's church.
Picking a patron deity for our characters made it seem like they might be more important but that ended up a letdown. I'm guessing they had a lot more significance in 1.0 than they did in 2.0 and onward.