The inventors of Iron Working and War Chariots the Hittites were still a major Civ. The problem at the moment is, that Sumeria get as UU the Warcart and not the Phalanx. So there is a problem with the implementation if you do not change Sumeria at the same time. The Hittites armies were very fast, so that they were capable to take Babylon in an coup and smash the First Dynasty of Babylon. The UU should be an early and cheaper swordsman. The Egyptian–Hittite peace treaty could be the base of some thoughts about their UA. Short after this peace treaty was made they sign an alliance. So the UA could be that after a peace treaty the attitude of the other Civ will be resetted.