You're playing on king so I assume you know what your doing but it seems like your cities lack production.

i don't know.. didn't have that issue myself. I had a shit ton of science so most techs took like 4-8 turns and most buildings took 8-9 turns besides wonders of course. Even wonders were only taking 30ish turns.

Yeah, production is the new king of the resources. Probably need to nerf the science and culture gain and buff the production a bit.

So after playing about 150 hours there are a couple OP civs and one that needs major help.

Germany and Sumeria are certainly OP. Sumeria's War Carts are the best unique in the game and can roll just about anything till Pikeman come along. Germany gets a unique for the best district in the game and it gets bonus production from the 2nd best district in the game. Once the Hansa get online Germany can steamroll into any victory type.

Scythia and Rome are also pretty powerful as well.

Norway is by far the weakest civ as the berserker is costly and simply can not stand against Archers/Crossbow. The naval pillaging mechanic doesn't work as their is very little reason to settle on the coast as the game currently stands.