Matthew Gray Gubler has to return for Community's Paget Brewster) all set to return. However, one character who is conspicuous by his absence is Criminal Minds fan-favorite Dr. Spencer Reid, who Matthew Gray Gubler played across all 15 seasons of the series to date.
Criminal Minds' finale's first half makes Spencer Reid its primary focus, with the tortured genius at the brink of death once again, his time due to a brain hemorrhage sustained in the line of duty. While in this precarious state, Reid experiences a cathartic hallucination of his late girlfriend Maeve (Beth Riesgraf), which helps him realize it is time to be at peace with himself after years of harrowing experiences chasing UnSubs. After awakening, Reid eventually heeds this ethereal advice in the original Criminal Minds series finale, seemingly taking a consultation role that wouldn't see him permanently leave BAU, but would see him work less with them.
Nevertheless, Matthew Gray Gubler's Spencer Reid simply must return for the Criminal Minds show revival and season 16 if the Paramount+ reboot is to be a success. Reid is one of the most popular Criminal Minds characters in the history of the long-running series, meaning his current omission is hugely damaging for season 16's early potential. Moreover, bringing Reid's character back into the fold properly would be a simple narrative process given his brilliant-yet-fervent mind that inexorably pulls him towards solving mysteries.
Alongside Kirsten Vangsness' Penelope Garcia, Gubler's Spencer Reid is as near an indispensable character as audiences are likely to find on a TV series. Reid's various demons, and more importantly, his undeniable genius, have formed the backbone of Criminal Minds' seasonal narratives more than any other BAU member. His absence, therefore, robs the other BAU agents in Criminal Minds of their force-majeure factor that solves the most complex cases while also disappointing a dedicated fanbase that prizes Reid's return above almost every other character in the reboot.
Additionally, Criminal Minds season 16 would not have to work very hard to explain why Reid can return to the BAU despite his spiritual awakening during his finale retrospective. Criminal Minds has repeatedly shown that Reid's mind cannot be switched off, with his mercurial talents of deduction always working overtime even when not at Quantico. As a result, it would be a natural step for the Criminal Minds writers to reveal that Reid has grown bored with his new life set up and needs to put his singular brain back to work right at the cutting edge of the BAU. Criminal Minds has weathered many casting storms over its extensive 15-year run, such as Shemar Moore's exit and Thomas Gibson's dismissal from the TV series, but failing to bring back Matthew Gray Gubler's Spencer Reid would be a glaring omission that the season 16 reboot may struggle to come back from.
