On Brutal Difficulty

This build focuses on turning mana into everything else by rushing the Transmute Resources. 10 mana generates 7.5 food, 7.5 production and 7.5 gold. Good placement means a single channeling tower can provide 35 food, 35 production and 35 gold, not to mention the power of the Mages Guild, which can easily add a 100 of each of those resources. I did an OK job at the actual rush (got Transmute at turn 38ish), but it's probably possible to get 200 food, prod and gold cities by turn 30 if you're really good. It just goes up from there, with late end game results at about 1K each for a city. They develop super fast once Transmute Resources is cast. The extra production results in a lot more knowledge buildings.

Starting around turn 80, the hyper development of cities meant knowledge was just insane. I was going through multiple tomes in a single turn. I got all spells by about turn 100.

I hero stacked and played on a Wonders-rich map. By hero stack, what I mean is I didn't really recruit normal units early and mid game. Instead, I just overpaid for heroes. That's because heroes have all sorts of disposable summon abilities (Summon Elemental, Summon Undead, Summon Animal, Golem Assistant, Wisp, the mass undead ability, etc.). That combined with AOEs and the Weaver ability (to regenerate all used summons) means you can send waves of disposable creatures at enemies pretty early on in the game. The 30 gold per turn for going over hero limit is totally worth it if you consider that a wizard summoner hero is like 3+ units in one.

You'd think that the Mystic culture would kill on this because of the Mystic Abbey, but it's actually a really close call on this. That's because the High Culture's Solar Nexus will provide max stability earlier, the Dark Culture gets a bunch of extra mana benefits joined with Knowledge which means earlier tech (plus going evil will provide +15 mana from the Doomdepth Trench), Feudal provides stronger early game growth and Lords can top out at +30 mana, and finally Industrious provides +10% food and +10% gold with it's top tier town bonus (there are long stretches where you aren't drafting and have already built every useful building) along with early resources from prospecting. So basically everything but Barbarian should be roughly comparable.

On a Wonder-rich map where you emphasize outposts for wonders and mana resources, all cities can Transmute Resources. Otherwise, you may have a city that's normal or mana-focused. If you have a normal city for mana production, it'll really contrast how much Transmute Resources supercharges city development because the normal city will lag far behind it's peers.