I have been tinkering around with the original (ver 1.3) of TTK and have a couple of observations from my limited exposure.
I elected to play as Wei. I did some trading with Wu and managed to get the Medium units technology. Having a lot of cash left, I proceeded to upgrade a pile of units in the army, mainly cav, but also some archers and swordsman and pikeman. At 60 upgrade cost for archers, swordsman, and pikeman and 90 for the cav, I was able to upgrade quite a few.
Shu open the festivities by moving what appeared to be most of their army to the north and moving their cav out front. I had moved some troops in the area and also had 2 of my corps markers filled up with medium cav to counter attack with, so Shu lost most of their cav and retreated back.
I played 10 turns or so and finally took one of the isolated Shu cities. The heavy catapult is brutal with a 12 bombard and 3 square range. I have a pile of them in the middle of the map now and should have no issues moving forward against the target of my choice. I am also in the golden age, so my cash is starting to build up again. This is also helped with the fact that growth rates are incredible and cities grow very fast, increasing tax base.
On the units:
Spearman are not worth much. I was disbanding some of them to help with production and reduce troop expenses. Should probably do the same to some of the naval units.
I am currently building a mix of medium cav and catapults.
Catapults do not have lethal bombard against ships. Perhaps they should.
Light cav has 4 pips at regular status and medium cav has 3 pips at regular status. Would think they should be reversed perhaps. Perhaps light cav could move 3 instead of 2 as well to add some mobility.
Will tinker some more when I get a chance (my civ playing time has taken a drastic hit in recent weeks). So far, I have been having some fun with it and the topic is interesting.