#1 He lacks the charisma

To become the face of a brand or of the WWE, a lot of charisma and stage presence is required, which would make the WWE Universe feel more interested and connected to a character.
In the past, men like The Rock, Stone Cold, John Cena, and Randy Orton all possessed and displayed immense charisma which made them the face of a brand. Not only were their in-ring skills outstanding, but they were also great on the mic, which helps them build their character and keep the fans involved at all times.
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Being the face of the brand is a lot more demanding than just being destructive in the ring. Not only does Braun Strowman have limited wrestling skills, but he’s also nearly dreadful on the mic, and has failed to build up his character well. Initially, Bray Wyatt helped build him, and the WWE’s social media has worked in building his character, without which he would have been just another monster on WWE.
To become the face of the brand, Strowman will not only have to improve his wrestling moves and skill-set, but will also need a man like Bray Wyatt of Paul Heyman on the mic for him to become as big as Brock Lesnar.