I don’t have a standalone mod specifically for bots, though I did previously upload some tweaked bots to the forum, they’re quite outdated now, though still playable with a few minor fixes. They do have quite a few flaws, however. That said, in the mod I’m currently working on, I’m incorporating the successful features from those earlier bots into an entirely new one. It will include various behavioral modes, pre-loaded tactics along with a few "dirty tricks" if I come up with any, and a degree of randomness in its actions to ensure it doesn’t feel too predictable or formulaic.
That’s right, I started a thread about AI quite a while ago, where I’ve been uploading those bots.
But the game's symmetry also depends on how players can play the civilisations. Directly modifying the civilisations to push them towards more distinct playstyles than they currently have would, in my opinion, be the first step. Today, by sticking to roughly the same playstyle and the same build orders or unit orders, all civilisations remain generally playable. If we play the Carthaginians with a more Gallic playstyle, the civilisation remains fairly competitive. The only real differences between the game's civilisations at the moment are different but rather abstract bonuses (especially for new players), different textures, and a few unique buildings and units that don't fundamentally change the playstyles...
In my opinion, we should (still) preserve 0 A.D.'s origins (AoE2) and draw inspiration from it. In AoE2 (or even AoE4), civilisations have things in common but still retain different playstyles! I haven't tried DE, so I can't say whether this mod adds differences between civilisations and meets my "criteria".
What could make a difference, and what I also feel is missing, is the diversity and depth of Petra's playstyles, and I completely agree with you on that! But yes, changing playstyles depending on the civilisation would make balancing more complex, and I don't think the developers would put in the time needed to do that at the moment. Is there a mod that has experimented with changing AI playstyles?
Anyway, we're starting to drift away from the original topic of the discussion