That's really great news. I've put suggestions at other points in the forum, but to summarise them all in one place:
1) Please have standard skill upgrade paths for AI heroes to use so that it builds its heroes more effectively. E.g. death magic summoner, bow using assassin, club using warrior, etc. etc.
2) If the AI is not always building in all its cities (as is apparently the case from the Fog Of War thread) it certainly should be! It should also be using all its Essence slots all the time if possible, with Meditation as a fallback option if nothing else is suitable. The Fog Of War thread suggested that it seemed to only be adding one city spell at a time, there isn't really any reason to do this.
3) The AI should put units within one move of each other into maximum size stacks if it can. This is most obvious after Tornado, but it also seems to happen when it's sending reinforcements.
4) The AI should target Outposts and loot more. In general, if it has a target of opportunity (e.g. it has a more important target but comes within one move of something it can take) it should get the thing within one move. If it gets to its goal it should immediately get another goal (so it can use up movement points). Settlers who arrive at their desired spot should immediately build, and the AI should then decide what it can do with that city or Outpost.
5) The AI should prioritise production and unrest production buildings more, especially on higher difficulty levels. I understand that different AI personalities may have different priorities, but in general they don't seem to prioritise production as much as they should. I capture AI cities after 100 turns and they still haven't built workshops.
6) In normal circumstances the AI should only train units in fortresses.
7) If the AI has just lost a lot of units it should add unit training to the front of its queues.
8) If its in defensive mode (it has a large enemy stack in its borders) in an ideal world it would use a different flavour of strategic AI, where it focuses entirely on defending its cities, training more units, building defensive buildings, using strategic spells to immobilize the danger stack, and try to build up a powerful enough stack or stacks to repel the invaders. In general it shouldn't move its units from its cities unless they're helping to defend against the danger.
9) Is the problem with creating mounted troops simply that it doesn't have unit designs for the mounted troops? In general I can't see any reason not to build its normal units with wargs or horses if it has wargs or horses available.
10) Not really an AI issue but it does seem to be quite a serious exploit; giving a hero a horse and then waiting for monsters to leave their lairs so you can steal the loot is just too powerful. Either a: the main monster group should never leave its lair or b: the main monster group should never leave its lair on higher difficulty levels or c: it should be an option to say whether the main monster group ever leaves its lair.
Thanks again for creating such a great game, I haven't enjoyed a game this much in a long time.