But... but... if it doesn't take place at least partially on The Sword Coast, it will be NWN2 in name only!
I would like to see more of Chult, that is, if it wasn't for all the Yuan-Ti. I sort of got enough of those in the Icewind Dales. Some Zhentil Keep intrigues? Kara-Tur? Some Celtic inspired adventures on the Moonshaes? Some underwater realm?
All else failing, they could try to convince us that this takes place before Icewind Dale and that it was the sword of Gith that eventually got stuck in the chest of that big white dragon