Some of the names mentioned failed on top in reality, which is an easy counter argument to the everyone gets a run modern philosophy.
Perfect got the hot angle in Nov 89, smashing Hogan's WWF title on SNME. His run with Hogan was considered to have then done soft business, 13K at MSG, 8K in Philly, etc
Steamboat's post Mania 3 run with Savage flopped. 1200 in Cincy, 2300 in St Louis etc. Plus his 89 run in WCW was botched and he and Flair drew empty seats by the thousands for their classic run.
Owen probably peaked with what he accomplished in 1994. Bret losing at Summerslam and winning it back from Owen at Survivor Series would have been fine I suppose, but Owen seemed to fit best as a Tully Blanchard like sneaky upper mid card heel.
Piper of course couldn't be trusted to lose, plus he still thought he was in the normal wrestling business and was messing around with Crockett and Don Owens while Vince was making him a millionaire.
Heel Jake in 91/92 would have been fine transitionally, but his drug use was rampant by then. In the 80s, I don't see it. By the time he put on some mass, Hogan and Warrior were entrenched. His B-show headliner status with Rude, Andre, Dibiase fit well.
Bad News Brown was sort of old and kind of fat by 1988. Getting a run with Hogan and Savage in late 88/early 89 was perfect. If wrestling was booked like today, then sure News could have gotten a screwy win in Dec over Savage, and lost it back at the Rumble or whatever, but it's no real shame in how things played out.
78-83 Dusty is a good answer. If the WWF wanted Backlund to step back for a bit and drop the belt to a Ken Patera, Don Muraco, Greg Valentine type for Dusty to beat.
In 1993, I was convinced Razor was beating Bret at the Rumble for the title. Hart was still earning his top guy stripes at the time.
Simmons would have been fine in 1997 had he beat Taker in a screwy fashion. Hart and Austin were carrying the promotion, so Farooq would have had help drawing.
Davey Boy was excellent if someone could carry/guide him, but his mid-90s stuff didn't hold up for me when he wasn't working with Perfect, Vader, Hart or Shawn. His Diesel PPV match is legendarily bad. Heel Smith loved his rest holds.
Dibiase's 1987/88 run as top heel was considered a disappointment as fans thought he was too small for monster killer Hogan. Adding Andre to the mix gave Dibiase the extra bulk on top of his cheap heat gimmick. (Slaying Sacred Cows here!)
My official picks are 1980/1 Ken Patera who was drawing in the WWF and NWA simultaneously.
1985 Kerry Von Erich was giving women orgasms just walking to the ring. He was doing well in trips to St Louis and Chicago as well. (Fritz should have expanded, or Verne should have paid what it would have taken to get him). This is a better answer for non WWF places though as 85 Hogan was printing money.