Except for Brock?
Strowman is over
Roman is over
KO is over
AJ is over
Nakamura is over
Ambrose is over
Rollins is over
Bork transcends wrestling, barely. But he does. But to say he's the only one over? Nah.
You said incredibly over, none of these guys are incredibly over. They're over, to varying extents, and some them to much less of an extent to when they were in the WWE title picture. I'll go through them.
Strowman:
On the way up, has the double excitement of 'what would a strownman title run be like' and 'wow they haven't fucked him up yet' going for him and then the Brock bestowed attribute of 'man, brock's legit, that makes strowman a little bit legit for being good enough to waste his time'
Roman:
Come on. 3 straight WM main events will get you a reaction.
KO:
KO's a good promo and his matches routinely disappoint - his two most notable feuds this year have been Jericho and AJ Styles, both resulted in disappointing blow-offs. Maybe KO is capable of putting on a great match, but WWE doesn't let him show it. He is the rare and possibly only case on this roster of not fully getting over due to his lacklustre in-ring performance, despite good - and let's be honest, not GREAT - promos.
AJ:
AJ carries an aura of 'i'm the best wrestler in the world' around with him, which he had coming in. You are right, he doesn't need a title to be over - so is this good enough? He gets cheers and people talk about him online in a positive way, but he isn't exactly setting the world on fire with his current milquetoast midcard babyface run - this is an expenditure of interest and goodwill, rather than a generation of it. He bought an extension of this in his WWE title feud with John Cena.
Nakamura:
He is an entrance at this point who has 2 1/2 - 3 star matches, when he was supposed to be a potentially huge thing. They have recently, in his first major title feud, made it about race. His star will fade soon, the entrance will keep him breathing for a while but not forever. A complete disappointment through a mix of his own boring matches and a mix of meandering and right now, racially reductive booking.
Ambrose:
This one baffles me a little - he's a good promo, but he is so bad in the ring I don't know why people didn't give up on him a long time ago. I guess he's kind of hot, so women like him, and he can act a little - I guess in this extremely meagre linup of 'incredibly over' people he does make the cut. People went nuts for his title win, and his close call with Triple H - a WWE title match which is the best match in his WWE career.
Rollins:
Rollins got over because he had a long fucking title run where he had a series of great matches. He gets nothing compared to what he got then and there's a correlation there.
