3. (Not So) Secret Invasion
A relatively popular Marvel Comics crossover storyline, the Secret Invasion arc was delicately touched upon with Loki manipulating some characters in The Avengers to do his bidding, which allowed for a sense of not knowing whether a character was friend or foe at first. This could be raised, however, with a return from the Chitauri- something which would actually be beneficial to the series budget given that that particular race is an old CG asset- as they inhabit the bodies of key characters secretly, perhaps over the course of a few episodes so as to further the level of pay-off for loyal followers while Previously opening segments help to keep newcomers up-to-date. If the writing team could pull off even a minor rendition of the original Secret Invasion arc in a stronger manner than how Ubisoft are attempting to poorly do it with the Battle For Earth video game on 360 and Wii U, their episodes would likely be met with rapturous applause from both nostalgic fans and newcomers alike. Certainly, the intense and dramatic narrative of the original comic-book arc would lend itself to this kind of production, allowing for a kind of unpredictability that is lacking from so many other near-identical US dramas nowadays!