Currently doing my own, still heavily Hyborian influenced, world* and try to keep it on a more “realistic” side – so my vote would go to the inland sea.
However it´s still fantasy so I go with anything coming.
I don´t know if you are interested in it but the Hyrkania (eastern steppes) and Vendyha (India) regions aren´t much covered in many of the novels neither in many fantasy at all. Same goes for real life Himalaya region (Nepal, Tibet) which has some interesting implications (Hyborian Age Gurkha).
And speaking of units – in the Conan Unconquered game one of the most dangerous units is the Shem Ashuri Warrior.
So , lot´s of desert/southern stuff still to be explored. (Yes, punting for coming decades!)
*Think of it as Hyboria and GoT had a baby with all the political implications. Kane is it´s uncle and Lankhmar it´s aunt.
"In strange grammar this one writes" - Master Yoda