I didn't test yet, because I really want to start testing while making modification of RUL file for, say, XCF mod with, hopefully, non-whole aggressiveness/behavior possibilities. But some things might be insightful:
- There is lots of countermeasures against campers. Smoke grenades. Invisibility. Preventive rocketing/explosions on AOE (no-visibility/intuition). Tanking with heavily-armored unit. Speed.
While many of these things are still a challenge for AI to get into use, speed and tanking are matter of calculations.
I don't really remember the reaction fire chance formula, but I believe it depends on difference in reactions and remaining TU's between moving unit and observer. It's quite usual for middle-stage modded game that player-controlled units have 200 TU's and good reactions/bravery. These units will trigger much less reaction shots than ordinary 80 TU unit.
Tanking is different matter. If BAI could make such decision for better outcome without cheating, it would be nice too.
- The outcome is very sensitive to game balance, and it should be taken into account. There's limited profit to train BAI on fast-battles, because they represent only 1% of lategame scenarios, while major of most intense and interesting battles happen at early/middle game stage.
Balance is constantly shifting during the game: early-game missions yet appear (if mission source is not squelched), while new challenges appear. And those can be hard or easy.
Imagine a mission vs one single naked psycho with nuclear rocket launcher. One chance mission, he can fuckup the whole squad on turn one, while others - he will remain helpless in CQC, if player manages to go unnoticed. It's all about thriller
- As player, I will keep saying it again and again: there is 500-1000 missions to play. That should be, at least, fun.