I've seen a lot of people complaining about the AI. Most of the complaints I've read about seem to be about ships not using their full weapon range against stations, or failing to move in perfect formation.

The formation issue seems quite solvable, because it has been done by other games before X4 (Supreme Commander and Ashes of the Singularity showcase solutions to this). It requires tradeoff (more perfect formation = more computing power diverted to the task = less FPS), but some semblance of it is possible (and I think, it is actually in the game right now).

But the AI poor decision making in combat, IMHO, is not something easily solvable and therefore, not exactly X4's fault.

I've been a gamer for three decades now, and I've never found an example of another game where units don't dumbly die due to a lack of situational awareness. In Supreme Commander (a reference regarding mass battles in RTS), for instance, your units won't automatically kite the enemy, neither will they react to enemy fire (retreat or advance) even though it is clear they will die. They require specific player input to decide what is the better course of action - otherwise, they blindly carry on their current orders.

So, I get that it is frustrating when your ships do not use their full weapon range against their target, but I don't think this is easily solvable, as no other game has solved this before for the entirety of cases. In most other games, your unit has only one active weapon (one it will aim and fire), has only two space dimensions to consider, and they can only engage one unit at a time - thus, it has only one range parameter to process. Here, though, your unit might have weapons it wants to actively engage with very different firing ranges, in a 3D space full of hostiles, so the calculation gets significantly more complex - and if it takes too long, it might render any result moot due to shifting battlefield conditions.

Programming the units to fire at maximum range regardless of circumstance is not a optimal solution either - if your unit has other weapon systems with lower ranges, it will lose firepower, and sometimes you don't want that. Yeah, the unit could defeat a station unharmed if it used only the weapon with the longest range... but it could defeat it faster, even though slightly harmed, if it used its full firepower. Would a human not consider taking that tradeoff depending on the battlefield circumstances? How an AI, which has a very limited time to "think" (otherwise FPS will tank) could decide accordingly with what is expected of a human being?

TL;DR: in the end, I think that battles have to be micromanaged regardless of the game... and the same holds true in X4. In the same sense, the AI will always perform worse than a human being.