You won't find many turn based strategy games that are based on Chinese history. It's unfortunately a very niche market, and any games that there may be about them, they likely have not left Asia.
Your best bet would be to look at Strategy RPGs really. Fire Emblem, Tactics Ogre, etc. Might not be history based, but they're great games and have excellent stories.
Your other option would be to go the PC gaming route. There are some fan made modifications that change the era to various different Chinese dynasties. In this regard, I'd recommend Medieval 2 Total War, and then downloading the All Under Heaven modification once it's released.
It's a shame that companies haven't decided to push into this market like Koei did, but unfortunately it's very niche.
Honestly, I have to say that if someone were to make a game like Koei's ROTK and take all the best elements out of that, I don't care what time period it is in.
Also, as for games like ROTK, I am pretty sure Hearts of Iron 3 is pretty similar to ROTK, but instead of Chinese history it is based in WW2 instead. But it's not the usually stomper game, instead you play as a country and it has officers and armies and economies, ect. Look into it.
As for Fire Emblem, I'll never forgive the makers of that game for not taking an "Empires route", you know what I mean. Fire Emblem except it's like Empires, you can recruite your own units, name them, decide their class (depending on class it costs a certain amount of gold), and then they level up like normal and class up like normal. But it's like ROTK or Empires, and you have to station then in certain provinces or else the enemy could just run through them. It would be the best Role Playing Strategy game ever.
Also anything in the total war series should satisfy your strategy needs, I particularly recommend Medieval 2 Total War as it has aged well and there are many large overhaul mods for it, and if you have the patience you can learn to tweak it to your own liking.