I'm actually quite tempted to do a "between two seas" georgia run.
Tbilisi is actually an amazing early game location for a capital as well, besides the fact that most land to the east is cold arid. Right in the middle of a river, surrounded by solid RGOs with good food rgos to boot.
You've even got a decent natural harbour into the black sea on one side of the river with an amazing natural harbour into the caspian