#2 Other RAW stars like Aleister Black, Buddy Murphy, and Rusev are more over than Carillo
I understand that most of the people I'm suggesting in place of Carrillo are busy with other feuds. That wasn't the case, however, immediately following the draft. Aleister Black has had months of sitting in a room looking for a fight. He had sporadic matches throughout the year, but went back to looking for a fight backstage rather than just laying waste to people in the ring. Buddy Murphy appears to be answering Black's challenges, and I'm all in for those two facing off. It's just that either of those two men who have backstories to build on would have been better choices as challengers for Styles.
Rusev is embroiled with a crazy love triangle with Lana and Lashley, which is why he isn't challenging for the title. Like Black and to a lesser degree Murphy, Rusev is still over with the crowd. The audience routinely chants "Rusev Day" any time he is in the ring and despite his cryptic words, Black also elicits a good reaction from the crowd.
Creating a new Rey Mysterio/Latino star is clearly on the agenda, as evidenced by Carrillo's draft status. Mysterio also wished him luck during RAW. One problem with little backstory for the former Cruiserweight, however, is that WWE Creative probably won't get the crowd reaction they want, if he dethrones Styles.
He needs a little more time and seasoning on the bigger shows, so that the audience can truly get behind him. I'm not saying he'll be met with silence if he wins, it's just if this is the first step forward of his star ascending, it might not be as successful as the company hopes.