Just finished another round. This time I wanted a challenge and put AI income to 250%. On turn 11 I used AI's xp and veterans (forgot to do it on t10). It was more even this time. I stopped playing at round 18 because this bug kept reappearing (https://github.com/triplea-game/triplea/issues/7184). I think I would have won though.
Here are some more things I noticed:
Items have extremely different power levels. This time I got long range artillery. 2 movement for suicide ammunition was insane. Probably the best item on the map. All the +1 movement items are extremely good though.
One enemy got Skull of Guldan and War drums. I didn't know they stack into -2. That was also very powerful. He basically was a one man army. All the normal units don't stand a chance against him because they have barely any damage and with 3 HP it takes ages to kill him. I needed artillery for him (which made artillery even more important) Just imagine having Skull of Guldan, War Horn and War drums in one hero. 5 footman, 5 Spearman and 5 crossbowman having zero attack.
Ring of Retaliation gives +1 defense roll. It doesn't look like only the best roll is chosen. When you hover over the unit it says 2x5. The power on battle calc is weird though. On the unit it says 2x5 but power in battle calc it is 7. No idea how that works. Probably the same thing for the extra attack roll item.
Steel foot standard and Infantry field manual only work on normal footman not on veteran/elite footman. Seems a little weird, but maybe is intended?
Heroes only costing 10xp to revive seems way too low. I never even try to kill enemy heroes because it's just not worth it. On the same note killing my own is no problem so I use them for suicide missions. My personal opinion is that they should be more valuable. Probably costing a good sum of PU's (50-100) to revive.
Items are very fixed once the exploration rush is over. I would also like to see a way to reshuffle that later on. For example something were you loose some items to the killer when your hero dies. That way items could get reshuffled and great item combos can be helped by killing that hero.
Same thing with pets. They just revive for free every turn making them extremely valuable. It could just cost some mana and you can produce them in the territory of the hero.
There is also no description what a hero level does. Sometimes it explains itself, but sometimes I just couldn't figure it out.
Traps from night elves are quite strong. Creating a free permanent unit every turn is big even if it can't move. Totems from trolls seem similar but they don't have any HP.
You already mentioned it. AI doesn't build factories. That was very noticeable on 250% income. Humans just couldn't spend all their PU's.
Even though the AI had plenty of units around and killed every creep in their region they never attacked Gnomeregan. I don't know why that is but it is a disadvantage for AI.
Ents costing 150 wood seems a bit steep for their stats. It would make sense if they had 2 HP. Especially since elementals costing only 75 Mana with similar stats.
Wood in general is the most valuable resource for me because I need it for ships and artillery.
You can load artillery on transports and bombard the other navy. I am not sure if it is intentional but I actually like it. It just makes sense.
Tauren don't have a good unit for oil.
Guard is an extremely strong origin. Starting with one more unit helps you explore a lot. And then it is also a 5/5. And you get another one every ten rounds. Officer is comparable and there you don't have that unit at the start of the game. I would still take Guard if I didn't get another one every ten rounds, probably even if it was only a 3/3.
I like the idea that factions have similar strength and weaknesses. I really like the system in large middle earth were every faction felt unique. I think every faction should have a good land unit for every special resources though.
I never found myself building 2 HP units. They are very expensive. I know how easy they can become broken with attack retreat and all. They are tricky to balance. I think the big difference to other maps is: 1. artillery kind of already fills that role (free attacks every turn). 2. we already have heroes with additional HP that can be revived for a low price. 3. We have some units that respawn for free (hero pets and map specials like high elf village or ogre mound). 4. Targeted attacks mitigate their advantage because they can still die to 2 targeted attacks. 5. they are in very limited supply anyway thanks to special resources. It is not like large middle earth were you can spam Nazguls with all your PU's. I think you could experiment with the price.
I never build skeletons with undead. They compete against gargoyles over mana and air always seemed more important. Also the hero needs to be on a factory to build them. If I really have too much mana I can still build elementals for free too. I don't know what to think about them they are still a good deal in theory though.