#2 Johnny Gargano
Bare with me when I say this, but Johnny Gargano is what Vince McMahon wants Roman Reigns to be. "Johnny Wrestling" is the biggest baby face in the WWE, bigger than Seth Rollins on Raw, and bigger than AJ Styles on SmackDown. The fans connect with Gargano in a way that we haven't seen with anyone on the main roster, even when they boo they are merely voicing their objections towards his actions, and turn around and cheer him again.
Consider this, Roman Reigns has main evented the past four Wrestle Manias, he main evented Backlash with Samoa Joe in a match that meant nothing, while the WWE Championship got lost in the midcard. Now consider Johnny Gargano, who main evented every NXT TakeOver in 2018 thus far. Two of the four main events were for the NXT Championship, and the two that weren't surely felt worthy of main eventing over the championship.
Fans never got sick of seeing Gargano in the main event, the same can not be said for Reigns. Gargano has also had two five-star matches during his tenure in NXT. In the past year NXT has produced four five-star matches, and Gargano starred in two of them. The last five-star match on the main roster was CM Punk vs. John Cena for the WWE Championship at Money in the Bank on July 17, 2011.