I agree that there's a limit to how much map scripting can improve the AI's behaviour - but map-specific strategies.ai files are still useful to tell the AI when to attack or defend. The same basic script works for most maps, with different trigger conditions depending on the number of CPs on the map.
I definitely agree that the heavy British tanks unbalance Sidi Rezegh - the 88s can kill them initially, but once the British overrun the airfield it's incredibly hard for the Germans to take it back (especially when they get control of the 88s and point them in the other direction...) - Either replacing these tanks with more Crusaders, or giving the Germans some bombers, would
I've made a fair amount of progress with map scripting, Supercharge in particular - the Germans will now counter-attack once the British have overrun the central CPs (previously, an error with the trigger conditions meant that they would attack right at the start of the game, but wouldn't bother later on).
Sidi Rezegh also seems to work better now the British go on the defensive once the airfield + blockhouse are captured. However, I haven't had much success adding the mosque and British outpost to the script (currently, the AI doesn't recognise these CPs so doesn't spawn from them) I just get a CTD shortly after starting the map, but I'll keep trying.
I'll experiment with changing the Luttich script to get the AI to attack the main bases, but I'm not sure this will work very well - I suspect they'll end up driving into the anti-base camp radius and getting killed. A better way of improving this map might be to add more pathfinding routes through the open country, and/or making more bots spawn at the outlying farm and abbey CPs (the latter might be doable via scripting)
Another "tweakable" thing in the map scripts, which I forgot to mention in the first post, is the "vehicle search radius" for CPs. This seems to affect the area around a CP within which spawning bots are aware of empty vehicles. On some CPs (such as the main German base on Supercharge) it's very low, which is presumably the reason bots rarely seemed to use the tanks there.