Build multiple guys. Don't put all eggs in one basket. Rock had Stone Cold. Cena has had Orton, Punk and Bryan. Who does Roman have? No one near him. Why? Because no one is getting the big rubs.
You have plenty of talent like Braun Strowman, Finn Bálor and Samoa Joe to build on. Even Seth Rollins and Dean Ambrose. But you have to give them big victories like Roman got. If Lesnar leaves after Wrestlemania, Roman has no one equal as of now.