Materia would have been a vast improvement with some actual implications on gameplay. I can only imagine the awesome of calling down Bahamut to reign destruction on bases and ****. Or shiva to make a path to drive on Water, or Ifrit to set forests on fire to smoke out game and snipers, or Ramuh to call up thunderstorms alah Skyrim's Storm Call.
Or wait for it...
UNDERWATER TO BREATHE UNDERWATER