in the history of culture you're right it's obscure, but in the history of games I gotta beg to differ. Kunio basically brought the 'Bancho' character archetype to videogames for the first time, and without the product of 'Nekketsu Koha Kunio Kun' and 'Renegade', Double Dragon never woulda happened.
kunio-kun is a huge series in japan (with either rcr here or one of the dodgeball games being the core), and river city ransom is a huge game in the states. there is absolutely nothing obscure here.