The old hard/brutal didn't really make eco outside of a fixed trigger that was often ignored, they just boil out units. This is a good playstyle vs other AI but humans will reliably just defend, eco up, kill with an excellent attrition ratio and gradually roll it up across the map.
> Overfitted against kgb-13 playstyle?
certainly a factor, that was my primary source of testing vs raiding and aggression, but it was tested against variations of itself too.
Investing in eco is more of a versus humans measure, since humans have and usually follow the concept of stabilising a front and focusing on attrition. Bots tend to focus on raiding and attacks over everything else. A focus on eco means that the threat the AI poses continually increases through the game if it isn't continually raided (and most humans don't continually raid ).
You can make the AI competitive with its older iterations again by changing the number of preventative defences it makes per mex back down to 1 (currently 2) and restoring its old habit of turbo-spamming raiders all game, but that doesn't make for a good opponent to a human team.
Obviously it would be preferable that the AI could have more than one set of configurations so its behaviour could vary, but Lamer doesn't seem interested in this approach.