Let me first start off by saying that I think KK et al. did the best they could with the 6 year old game they had to work with. A lot of hard work went into this mod to give players an immersive experience. Unfortunately, Creative Assembly has better things to do than apply updates to a game when they are busy moving on to the next new thing. You can't really blame them, they are a business after all.
So getting to my main point, my single biggest complaint why this mod is broken is that the AI simply cannot play by the rules within the confines of the user controlled universe. I have heard the argument that if it were "vanilla AI" we would all steamroll, etc. But let's face it we are all just too good at this game. M2TW was made for a general RTS audience. TATW was obviously designed for the M2TW Fanatic. Why else would the recommended difficulty be VH/VH. Because we have all already figured out every nook and cranny to give ourselves the edge over the vanilla AI. Examples include creating super governors w/ no neg traits, easily being able to wage battle after battle after battle of epic, heroic victories. The list goes on. This in turn forces the modders to give the AI more buffs to deal with everyone's incessant manipulation of gameplay. So then the next necessary step is to turn up the morale for the enemy, give them free money, give them 10 star generals, give them free units. I understand other modders have been trying to address these issues via RC and enhanced C-AI, but they simply do not get at the root of the problem. That the AI cannot manage it's money or units. They are utterly broken.
I want to close by saying that I really did enjoy playing this mod. I think it does a really good job of immersing you into the JRRT world, which is really all anyone can ask for. I just think that after several, hard fought, grueling ashes in your mouth wins on VH/VH, only by having to tweak submods to your every whim just to have a playable experience, you can start to see the game for what it is.