I'm thinking level 10. From Savin's tile map he posted a while back, it appears that half the frost marches are available to the player, even if their content is not complete yet; the other half being after the foothills,
Also,
Even still, wonder if there any new planned places that weren't in the original idea of the game, maybe that way making it possible to increase your level more, maybe to 20? Since that seems to be the maximum or close to it in most dnd games (at least that's what my google search tells me).
with the last place you fight Kas being somewhere in the sunken city it seems?
Also,
if you steal some of her powers in WC with mirror magic, you can see them being level 10 in the abilities section of the journal, and since she is the last boss...
Even still, wonder if there any new planned places that weren't in the original idea of the game, maybe that way making it possible to increase your level more, maybe to 20? Since that seems to be the maximum or close to it in most dnd games (at least that's what my google search tells me).