I played 3 deity games, here are my top 3 for conquest victory.
Top 1 is Scythia.
-Nomadic ancient rush with mounted archers is my favourite gameplay style. Scythia is new version of Huns or Mongols, thats why i try them first.
-Their Horse Archer is the strongest early unit to beat AI. Hit and run until your enemy down. You heal when kill enemies, another thing make your horde unstopable.
-Sell your Horsemen for gold, double production with policies and sell them for gold, then use gold to buy everything (except some district, but who care about high end districts while you will beat all AI before industrial era?). This ability is OP, break economic balance, must be nerfed or something.
-Kurgan help you have an early religion, earn some military believes, then conquer everything.
Top 2 is Aztec.
-Like other players predict about Aztec in Beta, they are another top civ for early rush.
-Deity AI have plenty of units for Jaguar to kill, then build up an army of builders, that can rush district (only can be built, cant rush by gold). Many unsused builders left? Sell them for big gold, like Scythians, and another eco break ability.
-Again, we have faith building advantage for military believes, rush now, think later!
-Leader bonus make your empire never sink unto lack of amenities, everything be more possitive, more stable for new conquered lands. This aspect help Aztec keep 1 or 2 cities other than capitals each civs they conquered, compare with Scythia, they eat Civs slower, but can keep more benefits.
Top 3 is my most interesting Civ, the Russia. The Russian truly makes me suprise.
-Mother Russia is not strong like it look. Only tundra tiles you can work are hill, forrested and have bonus ones. The reason while Tundra is almost dead lands are we cant build farms or any improvements on tundra, even they have fresh water or river! This is unbelieveable and be a bad Dev decision compare to Civ 5. So, what Mother Russia gives you? few production (precious production, but still few), some other less precious faiths, in conclusion, its about 1-5 faith + production per city that settle near or on tundra lands. Remember, while you settle near tundra, you expect a low pop growthrate that will delay your developments significantly.
-Lavra is not ugly like it look, instead, its pretty strong. Its cost is halved, double faith produce (+2 instead of +1), with Mother Russia, most of the time you will be the first to get pantheon. Lavra +2 GPP, so likely you will be the first to have GPP and pick some strongest believes like Feed the World, that help your tundra city growth fast. Another + 1 WAM is suprisely strong, most of early WAM will be yours, even later on when you spam Lavra everywhere and with ICS strategy Russia follow.
-With your abundant Faith sources, your cities are almost double the faith income compare with other Civs. You can buy more faith things, and later medieval you can rush buy units with Theocracy.
-Late Medieval conquest is very interesting. Cossack is another suprise, they are stronger than they look like, this UU has strongest bonus Promotion, so you can steam roll enemies without loses.