Traditional Characters in Roots Section
I think that traditional characters should also be shown in the roots section for Korean lessons. I am sure there are many people like myself who have studied Japanese and traditional Chinese, so I think it would help some people.
Also, it could help people recognize hanja, if they are into that. Back when Korean was mainly written in hanja, and even today's hanja found in newspapers and names, there are no simplified characters. I think the traditional characters could be useful.