10 Reasons John Stewart Needs To Be The Cinematic Green Lantern
9. If Arrow Can't Use Him, Someone Needs To
Unlike Marvel, DC has no plans to integrate their movie and TV continuities together. Naturally, the movies take precedence, so if they want to use someone, it means that that character's off-limits to the TV side of things (aside from the odd case of there being too different Barry Allens). And, because of DC’s desire to succeed in all mediums, it doesn’t make sense for them to stockpile characters for the film world unless they fully intend to utilise them.
This character usage debate is particularly relevant to John Stewart, since rumour had him appearing in Arrow as the already established John Diggle. When producer Marc Guggenheim killed the fervour, stating “DC has other plans for that character,” it seemed likely that John Stewart would instead be coming to the big screen.
John Stewart is too important a character to not be used somewhere, so if Arrow can’t use him, then Justice League needs to. He's simply too valuable a resource to leave unused.