Every thing was scary looking in the 90s. LOL!
Well, Orka has never impressed me as a Namor foe. He was, after all, kind of like an Atlantean Hulk without the personality / characterization / theme. I mean, he was a dumb henchman of Warlord Krang! AFAIK, he really didn't have a personal grudge against Namor to motivate him.
I haven't read the comic, but apparently he had a conversion of some sort and was a hero in the Hero For Hire book for a short while, before he got killed off, again.
I still can't believe ORKA made it to the movies before Namor.