Wrestling Heels who shouldn’t be faces, Vice Versa

I see throughout these PG years, there is a group of fans who believe a John Cena heel turn is the way to go, but I think it will actually backfire on him and the WWE, as he is just better as a face and it is their own piss-poor booking and writing of his character and feuds that are at fault.  Which brings me to the question, who do you think are just better heels that shouldn't have turned face, and vice versa?  My picks:

Randy Orton:  I never liked him really, as he just comes off as the biggest doofus in the ring.  BUT at least as a heel he pulled off sneaky bastard quite well and was believable in just being bitter at everything.  As a face, well I don't even know WTF his motivation was for ANYTHING

Chris Jericho:  I would say minus his 2000-2001 run, because it was quite awesome, Jericho as a face is nothing compared to his Heel phases, especially the feuds he gets involved in.  Like he said in his dvd documentary when WCW finally decided to turn him heel after the Lionheart days, "Thank God!!"

Brock Lesnar:  The man is a monster, and should be booked like one, and Faces don't become Monsters, the rise up to take down that Monster.  Lesnar plays that role to a T and anytime he was made to be the good guy and not destroying everything in his path just seemed way off.

As for faces: I want to have more examples but my mind suddenly went blank. 

Absolutely agreed on Lesnar.  The moment he turned babyface I was like "This is gonna be bad" and it was.  
As for babyfaces who should never be heels:
I'm gonna go with Undertaker as my #1 pick.  Yeah, the initial character was creepy and effective, but once he started talking he would frequently take it WAY over the top far too often (Goat beard cult leader Undertaker, Booger Red Undertaker) and would generally swallow up the offense of the babyfaces.  I think it's no coincidence that his renaissance as a worker came with his babyface turn in 2004.  I find him better off selling these days.
AJ Styles is one where he's just such a natural babyface, and playing a heel he's always seeming to be putting a character on for the sake of the show.  
I'm sure there's many opinions on this one.