You're right in that Black Manta has been pretty credible since the 70s thanks to him killing Arthur Jr. and appearing on Challenge of the Super Friends. Ocean Master, however, was regarded as a joke by some during the late 80s and early 90s until Morrison put him on the Injustice League with Luthor, Joker, and Circe.
Aquaman has some other villains that are regarded by some as "lame" such as the Human Flying Fish.