I have no coding experience but I imagine that it would be near impossible to design a "good" engine for CEO without super-intelligent machine learning, on the basis that every army faced is going to be massively different. Engines for things like go and chess have the benefit of a pre-defined starting position of each and every game, as well as only having to assess a select few pieces. With CEO, however, I guess you would have to find a way for it to be able to evaluate the opposing army on its own as well as its strengths and weaknesses in relation to the pieces it is using... which would be a lot in and of itself, and the game hasn't even started yet lol

If you could find a way to do that, though, then I think that the best approach would be letting it figure out which pieces it likes the best on its own. Once it was able to determine that, it would hopefully have assessed the entire base of pieces well enough in order to be able to start playing itself to learn. I do not believe it to be possible for us as humans to assign number values to every move and ability-set within the game and how they correlate with eachother, so allowing the engine to figure this out for itself is almost assuredly going to be best. Letting it learn most tactical, strategic and positional ideas also would probably be the best way of going about it as well. I could not theoretically see a human being able to list each and every tactical motif and pattern possible and allow it to learn from these in this game like has happened with chess, as the rules of this game are much more complicated, as well as the piece potential.

Some things you probably could program it to be aware of, however, (and this is probably just obvious to a programmer, but alas I will say it anyway) are the basic rules, (uses of morale, morale drain past move 50, promotion, etc.) the basic chess tactics (skewers, pins, double attacks, overloaded pieces, discovered attacks, zwischenzug, zugzwang, interferece, etc.) the value of the center, the base value of pieces as well as their potential opening, middlegame, and endgame value, potential positional value, (eg; a Crusader+ in the e4, d4, e5, d5 squares is going to have the same board presence and effective range as a Rook but with additional benefits) counter-piece value, (eg; Antimage versus a lot of ranged and magic champions) importance of king safety, the value of minions being able to move backward, as well as synergies between pieces and just what does and doesn't work well together. There's probably a whole host of other things that could go here that I am not thinking of at the moment, too.

Once all that was done I guess it would need to play against itself many thousands of times against and with many different armies and strategies and develop a solid understanding of how everything works before it was able to effectively be of use to any human in assessing a position. Even after all of this, though, I still feel like it would have a terribly difficult time of accurately assessing the starting positions of every game because of the sheer immensity of calculation that this would require. I think for the time being, human intuition will always be better at this than a computer can ever hope to be only because time is a pretty big factor in this game. Give a supercomputer an hour to play its first move and sure, it will do better than human intuition but 5 minutes just isn't enough. As far as middlegame and endgames go, it would probably be substantially better than a human in assessment as tactics would be able to dominate the game and stalling techniques could be employed once ahead on morale.

Umm yeah that's about all I've got. Pretty fun stuff to think about! This post has inspired me to gather and sort my own collection of every piece in the game based on cost so I am able assess them better and gain a better understanding of the game myself. So thanks for that!