There are some people who prefer minimalism in Art and this is very skillfully was used in this temple, those lotus drawing on ceiling may be simple but due to that they do not still the show from the wood work. What I also noticed that the painting is not smooth like in some other temples, it has a texture, like in Impressionism still when slightly thicker colour are used to give an impression of three dimensional work.

As to dragon I did not know that in Korean culture it stays for water, the painting is very nice but as you say having a dragon that is carved out of wood must be more expensive and difficult rather then painting :)