That is a known issue - same goes for pre-2.8 version of the add-on. Apparently, it has something to do with keyframe interpolation. Exported animations and imported armatures work OK though, so it's not exactly high on my todo list.
I'm not aware of any hard limitations of KotorBlender, with regards to creating new characters. It may not have as many utilities as NWmax, it lacks tutorials, but you can certainly model, texture and rig new characters using KB.