In my forays into modding, I have gotten increasingly frustrated by the AI factions' inability to make an efficient army. They just don't seem to max out their open army slots and when they do, it is not with a good mix of units. Are we waiting for some new API or whatnot that gives the AI some army mixing strategies? What is the holdup? 

I don't know much more than the xml portion of the AI, but it would seem like a good idea to have some ideal army configurations that the AI uses to make an army. Something like:

Logistics 4: 2 Melee, 1 Ranged, 1 Hero; 4 Melee; 2 Heroes, 2 Ranged; 1 Pioneer, 3 Melee.

Logistics 5: 2 Melee, 2 Ranged 1 Hero; etc...

For each logistics capability the AI should be putting together an ideal army. If it cannot fill an army, it should stay home and wait for more units. Scouting is fine inbetween. I have set up some really well designed units for the AI, but since it is afraid of putting more than 3 good units in an army, I always win. Never even have to use magic. The only challenge I ever face are the armies of 9 from high level cities, which is the only thing preventing me from steamrolling all cities on the map. 

Perhaps an issue compounding this is the fact that threat ratings are too high. If the AI is determining army composition by using the combat ratings, that could be the problem. A unit of 6 leather clad troops with axes is not Strong. Strong is at least one Plate, all the rest in chain and a wizard hero. I am thinking about raising the requirements for threat levels, but it would be nice to know if that will have any effect on the AI.

To be fair, Brad is a busy guy and the changes he has already done just this last week are really good. I am thinking that he is waiting on someone else to finish some bit of code before he can fix the weakling AI army issue, because it is the biggest detracting factor to the AI currently. It seems like it would otherwise be the first thing he fixed.