#5 Shane McMahon

Shane McMahon returned to WWE after in 2016 after a seven-year absence, and that same year was appointed the commissioner of SmackDown when WWE announced the second ever brand extension.
McMahon did pretty well as the commissioner, participating in feuds with top stars like AJ Styles, and Kevin Owens and Sami Zayn. However, Shane took some time away from WWE TV back in April and now six months later in October, he has still yet to return.
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Now of course, McMahon was taking some time to heal some injuries that he took in his matches, as well as tend to his business dealings outside of WWE, but six months just seems like an awfully long time to not have the commissioner of the show be on television, especially having been featured on almost every episode of SmackDown in 2016 and 2017.
As it is Shane McMahon's show, I think his return, or at least an appearance, is long overdue and I can't think of a better night to return than the 1000th episode of SmackDown.