I've just now discovered this post as well as your other post about how most of the British artillery battery commanders refused the order to temporarily abandon the guns and hide in a square when enemy Cav approached. Thanks very much for your insight.
Not really an insight, more a case of reading what the people who were there wrote happened, rather than just what Wellington said he ordered.
Mercer was one of only a few battery commanders who left their guns in place during the French assault, and even he ignored Wellington's order to abandon them and shelter in the nearby square of Brunswickers. He states in his journal that looking at the petrified state of the children forming this square he concluded that if his men had abandoned their guns to ran towards it for shelter the whole battalion would probably have panicked and disbanded.
So, he held his position and his men stayed at their guns throughout, fortunately the low bank in front of his battery and the steep slope beyond protected his guns from being overrun.
One thing that constrains the game as a whole is the fact that the original release of the game on the 200th anniversary of the battle was EXTREMELY rushed in order to make that deadline. The result of this haste is that some errors were built into the game. I'm not sure whether all errors have been corrected, but, some have.
Well from my own testing and experience the AI does a pretty good job of coordinating the behaviour of cavalry and infantry, and I've seen cavalry and infantry tactic's in my games that mimic both the WRG tabletop rules and the tactical doctrines described in books like Imperial Bayonets.
Where the AI seems to fail badly is in its use of artillery. I've yet to see any combined arms cooperation between artillery and cavalry, or artillery and infantry, and the AI seems to treat artillery as nothing more than a static bombardment arm, often leaving it completely unsupported and vulnerable too. I suspect this is because that was how artillery was used in the ACW, and nobody found the time to change the AI before the launch of the game.
So, we basically have ACW artillery tactic's being employed alongside Napoleonic infantry and cavalry tactic's, which doesn't really work very well. The artillery really ought to be providing close and mutual support to the infantry and/or cavalry. But without switching off the AI by using the TC button that's almost impossible to achieve, and so far I've never seen the AI even attempt it.