The Korean color scheme is a little hard on the eyes, yes, but the colors are accurate! The colors are very recognizable if you've seen Korean art.
And I do think the Sejong leader screen is pretty awe-inspiring, lots of attention to detail and accuracy, and the colors are quite rich, rather than washed with brown ala Mongolia and England.
The Korean scenario is set in the
Imjin war period of 1592-1598, when Toyotomi Hideyoshi invaded Japan after they refused to let Japanese troops through to conquer China. Ming China and Korea allied to take them down, and this was Admiral Yi Sun-Shin's finest hour (Turtle ships), and Korean guerillas harrassed the Japanese armies as they ravaged the countryside. Eventually Yi Sun-shin was able to cut off Japanese supply lines by sea, even after having been decomissioned as admiral due to petty Korean court intrigue (he was accused of treason after refusing to disband the navy and join the army). Thus Japan was defeated by China and Korea. Also the hwacha saw lots of use, as in the Siege of Hwangju, where thousands of Japanese samurai attempted to storm a Korean castle, only to be turned back by rockets, rocks and other projectiles.
Concerning the
Wonders DLC, it sucks Sumeria and the Hittites are scenario-only, and that there are only 3 wonders added. But the good thing is the scenario will likely have unique units and art. I noticed the "Phalanx" unit in the video walkthrough, so hopefully unique Hittite and Sumerian units will also appear!