I image if there unlockables, people would have complained.
Edit: I need to add that if one were to think the Towers Mode in WWE 2K19 is pointless, did they also think the Towers Mode in Mortal Kombat was pointless. The difference between the two is that in WWE 2k19 you can advance with the damage you took from the previous match.
It is to test yourself, to see how far you can get. It harkens back to the Slobberknocker Match. There weren't unlockables in that, yet many found that match fun.
Just saying, that no matter what Yukes or 2k.do, they will be knocked for.something. put unlockables in the game and people will complain that they have to unlock them. Don't, and people will complain that it is pointless to play, because there aren't any unlockables.
Ciampa not being in is a legit complaint, but others are just stupid complaints, in my opinion.