Well, money wasn't an issue for the AI in my Swêboz campaign. The hard part was that for every stack I destroyed, another one took its place in no more than 3 turns. While that did create a tense atmosphere where I had to relieve besieged cities often, the strategies for each defeating them never changed. Essentially, the campaign was a long string of near-similar battles of epic proportions. The main problem being the similarity of all those battles.

I just tried playing a bit as Macedon on VH/H and I don't know if this would've also been the case as VH/M, but I found it very rewarding to be forced to defend Pella early on with subpar troops. I wasn't able to count on the AI's stupidity to win the battle! I set up two phalanxes (phalangite) in a V-shape at the only breach to slaughter the enemy. The unamoured Galatians warriors streamed in first and were decimitaed - I only lost 3 men. Then the cavalry came in. Same deal. But then the armoured enemy phalanx entered and it was a tough struggle... but the Hard setting gave them a bonus, and as such, my phalanx was no match. Luckily, I had engaged their general outside of the city walls with some reserve troops and forced him to rout. This left me with two weak reserve units (peltasts and slingers) and my general's cavalry - the enemy had three phalanx units marching slowly on my town square. With the enemy general out of the map now and little other way to defend my square with my own phalanxes out of commission, I engaged the exhausted enemy phalanx in the streets with my returning reserve units (the slingers fled instantly), and charged my general into the engagement as well. To my shock, the enemy's morale broke instantly, and 300 phalangitai were slaughtered in the rout that ensued.

That was rewarding.

I'm not sure if this is a fluke, but it seems that on Hard battle difficulty, morale is far more central to winning battles than statistical superiority. Something that I can definitely appreciate.