OK Firaxis, you made a pretty bad game to start off but it is salvageable. Here is a list of things that need to be changed in order for this game to be balanced and playable.
#1 Affinity is too important to get for free. Quests and Progenitor Ruins should not give free affinity points. It's just too ABSURD!
#2 The Slavs are mega op broken and need to be fixed. Slingshotting to anything including turn 42 battle suits is just bad, bad game design. Make it a set number of beakers or techs of a certain tier. ANY tech is just too much.
#3 Building Quests are too random and very strong. They need to consistently pop up or be removed completely.
#4 Prosperity is currently too strong, growth, a free settler, free worker, and loads of health is too much. The settler needs to be moved farther down the tree otherwise it is the only viable virtue option to start the game.
#4 Artists is too strong. Starting with +2 culture is so strong that all the other choices are null and void. You just get this one every time.
#5 Stations operate in a horrible mechanic. Randomly dropping and trolling your expansion locations is a very bad mechanic. You should be able to choose where they plant to some degree. Turning them off should be an option. Trading with them is currently too weak compared to your own cities.
#6 Get rid of gold from rivers OR make every player start on a river every time guaranteed. This is too luck based.
#7 The aliens need to be fixed, they need to be more aggressive. Currently they don't even attack workers and don't attack settlers 50% of the time. They should attack and pillage just like barbs did.
#8 Titanium is too strong. It needs to be toned down. +5 hammers is too much. Tectonic scanner is currently OP because titanium is OP.
#9 Crash sites and derelict settlements are too strong, loads of culture, 80 hammers etc.. is too much. Tone this luck based stuff down considerably. Culture pods, science pods and satellite pods are also a bit too strong.
#10 Internal trade routes are too strong, way too strong. Naval trade routes take it to a new level of absurdity. Tone these both down and bring naval trade routes closer to land based ones. The naval ones even seem to be safer IMO
#11 The hammer cost of marines and gunners compared to rangers and soldiers is way too far off. Were talking double the hammers for a unit that's slightly better. At the moment getting early affinity can actually leave you at a disadvantage if you don't have units ready to upgrade.
#12 The affinity unique units are way too strong and cost too little hammers compared to normal units. This is just crazy. A no brainer that these need toned way down.
#13 Purity is too strong compared to the other affinities. The teir 1 ability is by far the best and battle suits are stronger as well as easier to field because titanium is always abundant.
#14 Siege worms are way too strong and random. They are currently like random natural disasters. Isn't this a strategy game and not a roll of the dice type of game?
#15 The health system needs to be entirely revamped. Going negative health currently barely has any negative side effects. There should be steeper growth penalties for going negative. Going past -10 should be very bad.
#16 There needs to be some benefits of going tall. Currently the strategy every single game is to make as many cities as possible, land grab and get up trade routes. This is not strategy, it's the same thing every time regardless of your terrain. There should be some buildings that give you more science for having more citizens in your city or something similar to that. Going tall currently has zero advantages what so ever.
#17 Africa is total crap because the ability is void as soon as you go negative in health. Most of the game is spent in negative health. Africa needs reworked.
#18 Knowledge's first virtue is crap for the same reason that Africa is crap. It is void as soon as you go negative health. This needs reworked.
#19 Settling on a desert should not completely nerf your city. Settling on a hill should not give you less food and hammers total than plains or grassland. Come one. Make hills 2 food 3 hammers or something.
This is all that I can think of for now. Making these changes would greatly, drastically improved the game.
#1 Affinity is too important to get for free. Quests and Progenitor Ruins should not give free affinity points. It's just too ABSURD!
#2 The Slavs are mega op broken and need to be fixed. Slingshotting to anything including turn 42 battle suits is just bad, bad game design. Make it a set number of beakers or techs of a certain tier. ANY tech is just too much.
#3 Building Quests are too random and very strong. They need to consistently pop up or be removed completely.
#4 Prosperity is currently too strong, growth, a free settler, free worker, and loads of health is too much. The settler needs to be moved farther down the tree otherwise it is the only viable virtue option to start the game.
#4 Artists is too strong. Starting with +2 culture is so strong that all the other choices are null and void. You just get this one every time.
#5 Stations operate in a horrible mechanic. Randomly dropping and trolling your expansion locations is a very bad mechanic. You should be able to choose where they plant to some degree. Turning them off should be an option. Trading with them is currently too weak compared to your own cities.
#6 Get rid of gold from rivers OR make every player start on a river every time guaranteed. This is too luck based.
#7 The aliens need to be fixed, they need to be more aggressive. Currently they don't even attack workers and don't attack settlers 50% of the time. They should attack and pillage just like barbs did.
#8 Titanium is too strong. It needs to be toned down. +5 hammers is too much. Tectonic scanner is currently OP because titanium is OP.
#9 Crash sites and derelict settlements are too strong, loads of culture, 80 hammers etc.. is too much. Tone this luck based stuff down considerably. Culture pods, science pods and satellite pods are also a bit too strong.
#10 Internal trade routes are too strong, way too strong. Naval trade routes take it to a new level of absurdity. Tone these both down and bring naval trade routes closer to land based ones. The naval ones even seem to be safer IMO
#11 The hammer cost of marines and gunners compared to rangers and soldiers is way too far off. Were talking double the hammers for a unit that's slightly better. At the moment getting early affinity can actually leave you at a disadvantage if you don't have units ready to upgrade.
#12 The affinity unique units are way too strong and cost too little hammers compared to normal units. This is just crazy. A no brainer that these need toned way down.
#13 Purity is too strong compared to the other affinities. The teir 1 ability is by far the best and battle suits are stronger as well as easier to field because titanium is always abundant.
#14 Siege worms are way too strong and random. They are currently like random natural disasters. Isn't this a strategy game and not a roll of the dice type of game?
#15 The health system needs to be entirely revamped. Going negative health currently barely has any negative side effects. There should be steeper growth penalties for going negative. Going past -10 should be very bad.
#16 There needs to be some benefits of going tall. Currently the strategy every single game is to make as many cities as possible, land grab and get up trade routes. This is not strategy, it's the same thing every time regardless of your terrain. There should be some buildings that give you more science for having more citizens in your city or something similar to that. Going tall currently has zero advantages what so ever.
#17 Africa is total crap because the ability is void as soon as you go negative in health. Most of the game is spent in negative health. Africa needs reworked.
#18 Knowledge's first virtue is crap for the same reason that Africa is crap. It is void as soon as you go negative health. This needs reworked.
#19 Settling on a desert should not completely nerf your city. Settling on a hill should not give you less food and hammers total than plains or grassland. Come one. Make hills 2 food 3 hammers or something.
This is all that I can think of for now. Making these changes would greatly, drastically improved the game.