Been playing the game for a bit, with all the DLCs and shit. I guess it was an okay time, even if it feels a bit lacking compared to CK2.
Anyway, my issue (and I'm sure I'm late to the party) is the allied AI. You can't rely on them at all. Sure, they show up for the most part, but then the only AI they seem to have is to follow you around, but at times they ignore battles you had hoped for them to join for some unknown reason. It's absolutely dreadful, and takes me out of the game constantly. And I can't fathom that there isn't a button to tell them to go somewhere, or where to focus. That's not the only problem though, since they follow you everywhere, they destroy the supplies in every county you enter, starving everyone to death.
I guess it will be too much to hope this will be fixed, as it is currently it is unplayable.
After 200+ hours of CK2 and 3, honestly I think army combat is the most boring part of the game. Its a system severely lacking in interesting tactics and strategy. It's generally just "slam bigger number into smaller number" with some minor optimizations in terrain and unit types. Every time I play either game, I feel like min maxing for gold is always optimal. You improve your demesne, have funds to raise retinues, and eventually you're so tall the AI just can't keep up.
I've always been a bit frustrated by the fact that you can game army movement so easily by pausing in between move commands and checking the "Arrival" dates to catch a smaller army. Like yeah, you could not do it, but then it devolves into a stupid game of reaction that isn't the least bit rewarding.
I'm tempted to say there should be a more involved RTS component to army combat, but obviously Paradox would never spend the resources designing or implementing that.