Right you have probably guessed it from the title XD
Looking around the forums i saw that a lot of players are into anime, especially things as SAO and Log horizon. so i thought of one thing that would be amazing
You say that the titans will be hidden in ancient temples and that you have no specific world size yeah?
How about you made a world like SAO, pretty big with the titan hidden, and when we find and kill the insane titan there will be a portal up to another world that has an entirely differnt biome and will look different. and then we have to find the titan in that world to progress up. i think that would be so extremely awesome, because if you make it hard to find people will search for it to be able to progress to the next world and they will have something to do.
This is purely a matter of taste, but from the way the world system works i dont see it as being that hard