This global data only applies for coastlines, right? If it did not, meaning the whole globe would be more accurately depictured, you could simply UNdraw a large area by freehand, like inland America, Eurasia and Africa, from the map. Perhaps that would reduce some of the file size? It'd be as a... layer.
Ah, probably not the way it works.
Needless to say, I would wet my pants in glee for a more accurate Norwegian coast.