Bjørn Sandvik does a great job explaining why the usual ways of projecting KML data don’t work well for world maps. For example, often “Greenland looks like the same size of South America, while it is actually 8 times smaller.” Specifying coordinate reference systems (CRS) in KML was one issue OGC struggles with when considering new features for KML. Do you think one should be able to at least “hint” at what CRS should be used for a particular KML file?

KML projections [From KML projections]