To briefly sum up the previous post, the player was too disconnected from the outcome and their role was unsatisfying, the enemy force and distribution of their units was random and too much to deal with, and the combat system was poor. I came up with three changes I hoped would improve things.
The first part of this worked well - guaranteed damage meant that something was always happening and made each turn feel more important, and you could recognize when a flank was taking serious fire, even with bad commander reports (when units are near being destroyed, their appearance changes even if their commander is still reporting them as healthy). The commander estimate of damage taken was a nice idea, but didn't really work - I never felt inclined to keep track of them between turns or make decisions based on them. You already have the relevant information based on what enemies the commander says are present and how much damage they report each individual unit has taken at the end of each turn, so it was effectively more information and confused things more than it helped.
2) The enemy will no longer randomly pick unit types to send, and instead will follow a script of unit deployments - for instance one light infantry and one light armour to a random sector for the first three turns, then pick the weakest sector and send one heavy infantry there for the next three turns, then send two heavy armour to the opposite sector. You will lose the battle if any sector has no friendly units in it at any time, and you will win if that hasn't happened by a certain turn number.
I didn't implement this as fully as I'd first intended - the idea would be to have a few different sets of tactics for the AI to use. Instead I created one, which worked in the following simple way:
Turn 1-4) Send one Light Infantry to a random flank.
Turn 5-7) On turn 5, identify flank where player has least reserves positioned, and then send one Heavy Infantry there per turn.
Turn 8) Identify flank where player has least reserves, and send two Light Armour units there.
Turn 9-10) Send one Heavy Armour unit to weakest flank previously identified in turn 8.
The idea being that the enemy sends in a decent force of Heavy Infantry, hopefully leading the player to move reserves over there, before switching target and sending an armoured force to one of the flanks they might have left less defended. Despite this fairly simplistic system, it did help a great deal. I think a lot of the improvement also comes from the limiting of the enemy forces, so that you can overpower them if you deploy your reserves right, and the fact that there is now a win condition (I didn't code it in, but since the enemy units stop arriving at turn 10, I figured that if you can last to turn 12 or so without having a flank with no units at the frontline that would count as a victory).
Combined with the guaranteed damage every turn, there's actually some sense of a battle and of trying to hold a line, plus you have a frame of reference for whether you are committing reserves at an early point or a late point. If I had added other enemy tactics, sometimes they might frontload their stronger units - with the strategy described above you're obviously better off holding back your heavier units to counter the enemy heavies, but if you weren't sure which strategy the enemy is using then you'd be more inclined to consider sending in heavy units in response to early commander reports of heavy units (which could be false). I also reduced the toughness of units so that they are removed after taking six points of damage, rather than nine, which fits much better with the set game length.
3) Add some abilities to the heavy infantry and heavy armour which take effect when you commit them. The heavy infantry reduce the current damage of all allies in the sector by two when you send them in, and the heavy armour will damage all enemies in the sector one point when they go in. This will hopefully lead players to want to hold back heavy infantry until other units have taken some damage first, and you want to send heavy armour in when there are a lot of enemies in a sector.
This is the one that didn't really work, in part because the idea itself wasn't great, and also because I didn't implement any visual effects to go with it. Since I was mainly interested in changes from a gameplay point of view I simply added these effects in the most barebones way, with absolutely no feedback to the player whatsoever. But since the thinking behind this point was to hopefully make you feel a bit more involved in the battle and to make your actions feel a little more important, that lack of feedback is a serious issue. If you had seen explosions as the Heavy Tanks move in, or cheers / some kind of magic healing popups as Heavy Infantry join an area, it could have made them satisfying to use every time (obviously this applies to everything from the most core gameplay elements to the most minor sub-menu buttons, but if you're going to be lazy in your prototyping, at least make sure it's done for those core gameplay elements).
However, I don't think it would have mattered too much since even with full knowledge of what was happening, I still didn't really care. Since there are currently a fairly large number of units in the game, the bonus effects of these few units were basically drowned out in the regular combat damage - you'd notice the extra damage they dealt to the enemy more than the special bonus when they were committed to a flank. Even if you contributed all your heavy units at once (two infantry and one armour unit) I doubt the combined bonus effects would really feel substantial.
Altogether, I think these changes helped with the general combat and the performance of the enemy. Having a win condition also made a big difference (duh!) This should have been in from the start - I was looking solely at the systems of the game and hoping to get them nailed down a bit before building in the goal, but they're too connected in a strategy game like this for that to really be viable. While you can prototype a platformer or arcade shooter and just have fun endlessly jumping around and blowing stuff up, in a strategy game the ability to evaluate your performance on something other than surviving is more important to the fun factor.
Which leads us to what didn't improve - even with these changes I still didn't feel particularly close to the action and I never felt like I was really doing anything clever or stupid. I was just... doing stuff. The reason is linked to the concept itself. I actually succeeded at making a game where I was playing without perfect information, despite knowing exactly how all the game systems worked - I even knew what 'personality traits' each flank commander had, so I knew the odds on them making bad reports were. But combined with the other game systems, this wasn't fun at all. I think I made a mistake in having the combat as detailed as I did (even though that's not detailed at all). The focus was supposed to be on your evaluation of how accurate your commanders were rather than the details of the battle itself, and this is another serious fault - the commanders are hidden. They don't have names, faces, or characteristic styles of speech. If you came at the game blind, you wouldn't even assume there was any difference in how the different flanks report things.
The whole point of the units and combat was to give you something to measure your commanders by, to see how their reports fit with what you were seeing. But that just didn't happen, and there was almost no way for you to verify reports or get a second opinion. It would have been better to abstract the fighting much more, and perhaps make you decide on requests from your subordinates, rather than sending orders yourself - e.g. left flank would ask for extra tanks, and you agree or disagree. Combine this with either observers you can send out for special reports from flanks, and/or multiple commanders in each zone, and perhaps the concept would have worked better. I also think that it would work better across multiple battles, so you can really get to know your commanders.
I still think a game based around making these sorts of decisions could be interesting, but the design would need the characters you work with to be far more central, and the choices you make should be big ones, not shifting around a bunch of mostly minor units.