That's an excellent thought. The guy who wants this map prefers that I keep the shape and relative placing of the northern continent, so I'll probably just establish a new scale for the new map.

I may be able to justify the different shape with the topography. Perhaps the northern continent is a newer, growing continent, with higher, harsher mountains and rougher terrain that hasn't had much time to erode into smoother coastal plains, while the southern continent is older and more eroded?

Alternately, I could just make the southern coast a bit more jagged. I have a little wiggle room with the source map, thanks to those ludicrously wide penstrokes marking out its coast.