No, medium AI is fine. It's about the level a somewhat competent player can beat consistently after 1-3 tries. AI can be made easier by decreasing how many units they produce (e.g. Very Easy AI stops producing units when it hits 1/4 of max population), and only advancing to Town Phase / City Phase when the majority of human player clicked on the update. Giving units / buildings bonuses to their combat stats is a terrible idea. It makes it virtually impossible to learn the game. You cannot learn to gauge the strength of your opponent's army, and learn how strong different unit classes are if AI units "behave" differently. Discounts seem pointless when you already have an eco bonus. The only one that looks acceptable is training time discount.

To be honest before trying to make Civs unique the focus should be on making units more "unique". If an army of Spearmen, Archers and Cavalry Swordsmen, an army of Pikemen, Slingers and Cavalry Javeleers and an army of Swordsmen, Javeleers and Cavalry Archers would be gameplay-wise noticeable different from each other making Civs feel more unique would be a lot easier. Temple also needs a rework. Remove all techs aside from maybe Living Conditions, and create a bunch more interesting ones, like bigger healing radius for Temples, increased RoF around Temples, several techs giving giving Healers different kind of auras and so on. Then each Civ gets only a few of them. Healers themselves could also be made more unique. Like a Surgeons heals idle units / units in combat with 5 / 1 effectiveness, Doctors 4 / 2, Priests and Druids 3 / 3.

The Crush damage type is a mess because it incorporates three different kinds of attacks:     Small blunt objects, e.g. stones     Blunt objects with a lot of mass, e.g. maces     Anti-Building attacks, e.g. rams This will always lead to weird gameplay implications. E.g. currently Slingers are more effective against "lightly armored" targets as they should be, but they are also somewhat of a siege unit. Macemen behave more like arsonists with high anti-building damage but low damage against human units, especially heavily armored ones. How to fix this?   Idea 1: Two "new" damage types: Thump and Crush_new Slingers deal (mostly) Thump damage, and resistance of units is similar to current Crush Resistance. Low for weakly armored units, significantly higher for heavily armored units. Like 1-5-10 for infantry ranged, infantry melee / champion ranged, champion melee. This tries to simulate that the Sling loses comparably a lot of its lethality against armored targets. Crush_new is the damage type Macemen and partially Axemen deal. Crush_new resistance would be fairly low, like 1-2-3. This tries to simulate that maces and to a lesser degree axes have so much kinetic energy that armor is a lot less effective against it compared to how well it protects against e.g. swords or arrows. With two new damage types it would also be easy to incorporate them into Forge techs; Pierce Armor upgrades increase Thump Res, and Hack Armor upgrades increase Crush_new Res. Siege units get their own special damage type, or a bonus against buildings. E.g. a Ram deals Pierce and Crush_new damage and has a huge bonus against buildings. One issue with this idea is that very few units would use the Thump damage type. Mostly just Slingers, and maybe Onagers.   Idea 2: Blunt and Piercing Both Slingers and Macemen deal Blunt damage. Blunt Rest is similar to current Crush Resistance. Macemen also deal a little bit of Piercing to simulate them being good against heavily armored targets. Units would have 0 Piercing Res, and buildings a very high one. This would also enable the option to make other units relatively good even against heavily armored targets, e.g. Bolt Shooters. Against, Siege units would either get their own damage type or a damage bonus against buildings. One issue this idea has is it's hard to decide with Forge Armor upgrade should affect Blunt.   Idea 3: Crush_new Crush_new Res is something like 1-2-3. Only weapons particularly effective against heavy armor have the Crush_new damage type, e.g. maces. Slingers deal only Pierce damage, but have a bonus damage against ranged units to simulate the Sling being effective against unarmored targets. Siege units deal either Hack, Pierce or Crush_new damage, and have a damage bonus against buildings. This doesn't add any new damage types, but has to heavily work with bonus damage. The issue is if Forge Armor upgrades should affect Crush_new Res, and if so which one.    

Also @victorcrimea is working on dedicated servers.

I've seen several posts that suggest that the current Petra is too difficult, after my changes to its behaviour. My question is, should I make new PRs to nerf it Also what about creating more granular difficulty levels? For example we can lower the very easy to even lower and add some more extreme levels. Currently the only cheat of Petra is in terms of eco. We can give the extreme levels other cheats such as bonus to atk, unit hp, building hp, unit movement speed, training time discount, projectile accuracy, armour, price discount...