Is it not map specific? And if so, who the heck cares.

You put the sun where it best gives you the effect you are looking for [sunset city, etc.]
When the map is made, the top is north[pretty sure] and once you start mapping, you cant just change that. You set where the sun is, and there you go.
Shadows come in after running lightmaps which take the position of the sun you chose into account and get shadows from there. If you move the sun, you should rerun lightmaps to get them to be accurate to the new sun.
A realistic sun would only be important if you were to make a Stonehenge map. In which case you better put it in one of the right locations.
But come on, navigation? Ive never heard someone in PR say "He's ten degrees east of the sun" or "We're heading out towards the sun, then cutting east". If you wanna blind your opponent with the sun, the degrees on your compass being off have no part in that. You'll just be blinding them from a different direction
Lol.
ps i love winks and smileys. my bad.. go overboard now and then...
