I have done a lot of research on why the Summerians have a good advantage over them.
Yes, it may be true that Hittite cats rule sumerian, but let's look a little closer at the economies.
I have played Sumerian against Hittite and found out that Sumeria could afford the upgrade to Heavy Cat way before Hittite could.
The key trick to this is to send a villager to an open field in the bronze age, and build a Town Center. The moment he's done make a vill and send the builder to a farm. Once you vill is produced build another farm and so-on, untill you have the total room of 16 farms around your Town center. (remember to keep pumping vills from your original TC and sending them to wood (atleast 8 vills on wood in bronze, since you'll need to keep up on that wood for farms). And you also know what a lot of farms means right? it means lots and lots of War ellies, which can out number the hittite ellies/farm power. Now a Sumerian Heavy cat has 150HP, and a hittite plain cat has 150hp. but the sumerian one will win cuz of the 50% fire rate, and plus large damage area.
Now I would be extremely suprised if Hittite ever got to Heavy cat befor Sumer. You'll spend almost all your recources for Heavy cat with Hittite, when Sumer can outstandingly afford it way before Hittite! When I play Sumer, upgrading to Heavy cats is one of the easiest and soonest thing for me, and I still have plenty of food for tons of war ellies and HA's. And I'll be sure to invade with my heavy cats before hittite gets that upgrade.
continue adding comments, but please, be resonable?