Didn't try to mod any of the Nu-TW games outside Shogun 2. Not even Shogun is properly moddable, I'm afraid we will never see Med II or RTW tier mods. Greedy bastards decided they'd rather be covering any niche historical period like early Medieval Britain rather than let people have fun and mod their games.
To hell with it, maybe I will buy it on the summer sale but CA's marketing model is a joke. They sell FoTS as a separate game now for fuck's sake.
Also I believe that waiting for the summer sale before buying Bannerlord would be the smarter thing to do.