Did McMahon really believe that the Red Rooster gimmick would work, or was it all a rib on Terry Taylor? Also, outside of the Undertaker and maybe Doink, what would be on your list of the gimmicks/characters that should have outright bombed, but for some reason succeeded?
The Rooster deal wasn’t bad in theory, with Taylor doing the put-upon underdog role before turning on Heenan, but the problem was that he was turned into a curtain-jerker with Brooklyn Brawler. Oh, and also that he thought he was a fucking rooster. I’d say the second one was the bigger issue, personally. By that point it was just a rib on him anyway.
As for the gimmick deal, Undertaker was a star-making gimmick from the start. That never would have bombed. My #1 "how did this work?" choice would be Rockabilly teaming up with the Roadie and somehow becoming one of the top tag teams of the decade.