So on viceroy difficulty I managed to complete Roman Empire UHV on second attempt.
Man I had fun game. After I understood how laves worked game got much easier. I steamed Greece first and then divided my troops to collect Gaul and Iberia. Second army took islands and finally Carthage itself.
Then I understood I needed to hurry and work was colossal: I needed to conquer whole eastern Mediterranean sea in very short time. I lacked troops and and in Iberia I had no troops to guard cities so barbarians took over them. Luckily cities were poorly guarded, like only 1 or 2 units and they were no match for my legions. Quickly I overrun Turkey, Judea, Pontus, and finally Egypt. First UHV goal was completed and I even had some extra time.
Second goal was very easy, just build farms around Rome and set food focus and it is done.
Between 1st and 3rd goals my research was on zero and I still lost money! But then I understood that fairground + forum were necessary in every city. I build them everywhere and soon I was able to research again. Golden ages also helped me a lot because of extra production. My commerce simply exploded and I stopped printing money when I had 4k of it.
3rd UHV was a bit more difficult but I had plenty of time. Vercingetorix downed me and raided two of my cities. Gallic warrior is insanely powerful but he had only two of them. After I killed them taking his cities was more than easy.
Dacia was very difficult to conquer. Their UU has 5 strength and +100% against melee units. Like WTH? But again AI did not build them enough but taking their capital was difficult. I had three attempts before I succeed, even my veteran legions (all city raider promotions and two strength promotions) were unable to kill archers in their capital.
Meanwhile I colonized all places I thought would fit on my empire: Iberia, Britannia and multiple irrelevant islands because I had Colossus and GL.
Then last target was Armenia and Mesopotamia. Armenia was easy to conquer so no need further to discuss of it. But Mesopotamia, of boy. I had feeling that Parthian UU would be true Roman killer, and yes it was: a horseman with 5 strength, 4 moves and +50% against melee. Had AI had like 4 of them I would have had seriously difficult times. But it did not, I took all cities and accomplished Roman Empire UHV
So about modmod. I liked slavery feature a lot, it would be better if I was able to draft my citizens into slaves as well. But AI has no idea how to use slaves besides as workers, I never founded any slaves in AI cities so that might explain why AI had always very few units.
And then AI, it is very bad. Parthia and Dacia had really good UU but they failed to use them effectively. Gaul also botched its game when they also did not build UU at all. Often I simply had to wait that AI attacked against my units which were on better position and I defeated them very easily. Carthage AI did nothing to support its cities so I took them one by one. Egypt was to most difficult to take because it had so many units but again as often AI moved his units alone without support so easy victory. Also AI simply is unable to defeat itself effectively against barbarians. Civ like Nubia never did anything expect suffered because barbarians raided its lands all the time.
And more of barbarians. I liked how they were scripted. Holding Crimea and Dacia/Illyria was a nightmare because endless hordes of barbarians. If games tries to simulate why Romans left Dacia it is doing it right.
Few things I could not understand like why I was able to build workshops only in Egypt and why there are no improvements for hills expect windmills? Why there is a limit how many workers can I have? But how fishery works is really nice: +1 food from sea tiles or +2 if tile is next to city. Finally big island cities!
And then diplomatic AI. I understand that lot of wars are scripted to happen but almost every time AI downed me and then nothing. I could really ignore AI completely because it was so passive. Also some dows made no sense, like Axum downed me. They had score of 200 and I had over 1000 and two vassals there. Why would they want to kill themselves? Trading AI was strange also: "do you want this tech that takes 8 turns to discover, give me your 40 turn tech and 3000 gold (no spelling mistakes here)". I understand that tech sharing is not part of ancient world but cant you then disable it at least? Finally AI should really be scripted not to ask player to join war against civ that is have no border, like some Chinese civ asked me to join war against Vietnam

But after all this mod is a masterpiece. I hope it will be polished more and I wonder why this is no more popular? It should be.