They are not generally ''baren'' (TWMP Hammerfell and TWMP Skyrim have decent content added to it) but if you compare what we have with years this society had to build upon TWMP heightmaps, then yes, it' barren. Actually, when ''Black Marshes'' developers decide to release first beta, we will only have 3 provinces empty (for all i know, it's possible someone is working on them in the moment when i'm writing this): High Rock, Summerset Isles and Valenwood. Altough first two currently don't have any released mod that add any content to it (beside just making them use TWMP heightmap), Valenwood has it! And it's really nice mod with a lot of content it's just need someone who is willing to take care of little landscape issues down to the south of the province.. It's such a pain to the eyes (and brain) knowing you have awsome mod/content to fill Valewood province yet you can't due to it being incompatible with other provinces :/