#2 EC3

It feels like we haven't really seen a new main roster superstar challenge for a world title immediately after being brought up - or at least, we haven't seen it in a very long time. EC3, who recently debuted down in NXT, already feels like a guy who is destined to make a big, big impact on Raw or SmackDown Live in the not so distant future.
His character belongs in the big time, and in many ways, he feels like an improved and refined version of Bobby Roode. We could easily see him winning and losing the NXT Championship between now and Survivor Series, and then by the December pay-per-view, he's already on the main roster challenging for the Universal Championship.
Becky Lynch has been challenged HERE.