Jothar and everyone else: The Seforim don’t say to Daven east. There is nothing special about the east. We daven toward Eretz Yisroel. If you are north of EY than you face south…
The Shulchan Aruch Harav and The Emunas Chachomim (1600s) actually say to face the shortest route to EY. They actually give the formula to figure it out. It was basically not Nogeya in Europe, since it is much closer to EY. Therefor most Seforim will just mention that if you are north, you should face south.
As far as the Torah being meant for everbody: The Torah has many complicated Halachos that are mastered by only Talmidei Chachomim. We are supposed to listen to them. Once the Rabbonim establish the direction to face when Davening, it isn’t complicated at all!
Besides, what makes the latitude line less complicated than the actual direction. Yes, now that it is marked on all the maps it became the natural way to view the direction. But honestly, if I were here a thousand years ago, neither of these would be any simpler to me.