-You can place 2 coal resources in Japan, or at least one in Kyushu, the Southern island, or Hokkaido, the northern one (preferably on one of the mountains).
- Remove the dormant volcano on th second half of Shikoku, and replace it with silk, while changing the silk south of the Kyoto starting location into beef, to better represent beef being present in that area... apparently it is rather famous for it.
These sound like excellent suggestions.
I had a look at england today and I think one way to improve it would be to the north. There are a few little island to the north around where England tends to place their 3rd city.
This area has the tar and the tundra hill.
I think this area should be totally pimped out.
Firstly, I think extend it slightly further north, and then replace the tundra with some lush grassland. Place some extra fish and whale there too.
Then I was thinking we should buff the little islands a bit too, give them some resources etc.
I think also the path up to Greenland should be easier for England to reach by putting less ocean tiles and more polar coast. However, you don't want it too easy for Vikings to access, so gotta be careful.
Lastly, give Greenland a buff too with some more habitable tiles, and more resources.
This should give England a bit more of a leg up.
I think Arabia + Carthage could use a bit a buff too. I was thinking just below the mountain range where Carthage is, all the hills are desert hills - maybe change these to plains or something and a river. Also, maybe give Carthage another stone & salt around there or something.
Arabs i'm not too sure about, maybe to the south around the coast shouldn't have so much desert, more sheep and oases and stuff.
One last thought, Korea does seem a little bit cramped, maybe if there neighbours starting locations weren't so close they'd do a bit better. This isn't such a priority though in my opinion, those other 3 civs are in more dire need of help than Korea is.