10 Reasons Shazam Needs To Be In Justice League 2
2. Billy Can Call Backup If Necessary
A sequel to Justice League would naturally need to raise the stakes, presenting the League with a tougher fight than the battle put forth by Steppenwolf and his Parademons. Its core heroes would be at the front line, but that doesn't mean they'd fight alone. The first Justice League showed Steppenwolf's defeat of representatives from numerous armies, including the Amazons and the Green Lantern Corps.
Wonder Woman can continue to call on the warriors of Themyscira when in need of backup, and Aquaman's solo film saw him gain control of some incredibly dangerous sea creatures. Shazam, however, is the only character with five allies who possess all of the same powers as him. Not only that, but they may have some additional powers to offer as well.
The appearance of the Shazam Family at the end of Shazam! indicated that some of the team's power differences are the same as in the comics. Pedro has a bit of extra strength, while Darla benefits from greater use of her speed. While not shown on film, it would be sensible to assume that Eugene received his extra power from the comics as well.
Eugene's comic incarnation is able to control technology, a fact alluded to by the film character's love for computers and the weird hacking abilities he somehow learned by playing Watch Dogs. The Justice League has Cyborg for that sort of thing, but a backup technopath certainly couldn't hurt.
Not only could Eugene and the rest of the Shazam Family help current League Members fulfill their own duties, but their appearance as a united front could help turn the tides of battle at a pivotal moment. As stated in Shazam!, they're Billy's greatest power. The League would be wise to make use of them.