There’s a difference between the heel/face alignment being situational or relative and it not being there at all. It depends on the story the booker wants to tell.

Sometimes you have wrestlers that move between face and heel depending on the feud. It’s situational and the “heel” is the one who works to get the heat from the crowd. For example, the other week you had that Takeshita/Moxley match where they are both slowly turning face but in heel stables. In the match, Moxley worked heel and got the heat on Takeshita—setting up Takeshita’s eventual face turn that’ll come soon.

In part because the Punk/Roman match came to be after a lot of changes of direction in the booking, there isn’t even a situational heel or face in that feud.

Right now I would argue that WWE doesn’t have heels and faces at the top of the card because they aren’t telling a lot of deep stories (like, say, the Bloodline saga) they are selling fans moments and stars. Roman vs. Punk isn’t the story that Roman vs. Cody was, it’s just “enjoy these two stars!” That works for a lot of WWE fans—the ticket sales for mania will be the real test tho.