Most of AI's start working at cap. being at least 1000 unit. At GOG there is so far no way to increase unit cap beyong 500 (totala.ini doesn' work). Therefore there is no way for any proper AI to work as it should. Is there any way to get old good 5k unit patch for GoG and AI being suitable for that?

I think AI is hard enough on full metal maps, but for normal maps I agree AI is a bit easy. Anyway is a pain using many units, basically I'm not able to move many units at once because they start taking strange paths to reach destination. So unless there's a patch that also fix movement, iwould find useless increasing the cap limit.. because AI always move units in a more compact ploton than me (is really sad seing an army wich is double in power and number being harassed just because your units tends to separate instead of stayin unite.)

TA Universe has a pre 4.0 beta patch made by the still active TA community that solves most of the issues with TA improves pathfinding, ai, ups unit limit to a default 1500 vs 500 and you can change it up to like 6000. I have had no problems with the patch whatsoever and still use my 3 favorite mods with it. Won't let me post the links for some reason or I would.... but it can be easily found with any decent search engine.

Total Annihilation v3.9.01 Beta Patch over at TA Universe