This is an important one:

Leviathan and Odin. Those two had been summons in every FF since summons were introduced, as were of course, Shiva, Ifrit and Bahamut. So why leave them out now?

A big thing was made out of how there were four main elements and how they were opposites and everything, we have fire, ice and thunder summons but no water. It just shows a lack of communication between the people that made this game.

And as for Odin, I think he should have been there instead of Yojimbo, for example instead of Zanmato he does the infamous Steel-Bladed sword.

*Kills Square for forgetting them, deliberate or otherwise*