2. Sasha Banks
Roman Reigns was purportedly earmarked, from very early on his WWE tenure, to be the guy or at least a very significant figure in WWE. Dean Ambrose also seemed to have buzz around him for the level of character work he had developed on the indies, and fine efforts in developmental. But Seth Rollins? For as athletically remarkable as he is, and for having won an NXT Championship, he was nonetheless the guy with the least clear path forward. The Shield lent him an immediate character, set up his historic heel turn, and paved the way for him to be a top tier star.
Sasha Banks was similarly excellent to Rollins in NXT, and enjoyed a push for her first year and a half or so on the main roster, particularly in her title feud with Charlotte Flair. However, she has since gotten lost in the shuffle, at minimum lagging far behind Flair, Alexa Bliss, and Ronda Rousey.
Participation in a new version of The Shield could be just the ticket to reinvent Banks and make her relevant again. On top of that, her organic popularity and wrestling talent would fit nicely with the group.