Hello! Philip here. I've been playing something like 10 turns into a Pontus campaign. The mod is shaping up nicely, having followed it for a while. My general impressions of the campaign so far are that the economy is fairly balanced and challenging - you can recruit units, but pretty quickly you'll need to conquer new territories or raise taxes to provide their upkeep. I enjoyed starting out with two armies (as Pontus), allowing for some variety of military options early in the campaign. Public order was, perhaps, a bit too easily managed, at least in early game. Increasing taxes to the highest level didn't see public order go below 110%, even in newly conquered rebel territories.
Something that caught my attention was the implementation of a supply system via traits. Clever idea and execution. It's working well, and besieging enemy cities or staying for too long in enemy territory seems to yield some rather unpleasant, and realistic, problems for your army. I also liked the use of building chains as administrations in conquered territory - deciding on what conditions to impose on the vanquished. I didn't play for long enough yet to see this in effect, but culture appears to be playing a significant role in expansion, based on the tooltips I've read. This seems well considered, and I'm excited to see what the exact implications are for conquering a region with an entirely foreign culture.
In terms of bugs, I encountered a few missing sprites. Eastern skirmishers lacked such, as did flagbearers and officers in some eastern infantry units. See images in spoiler. There's also an issue with closing the game, which I'm sure you're already aware of.
(http://i.imgur.com/jZo44lB.jpg)
(http://i.imgur.com/9MtPTZA.jpg)
(http://i.imgur.com/VTNMVGK.jpg)