4. Thunderbolts
Thunderbolts carries a great premise: supervillains, inspired by the success of the Avengers, work to pose as heroes to pull off the ultimate heist. However, most of the team enjoy being heroes so much that they remain on the straight and narrow. The idea is solid, and like the team itself, it builds naturally on the success of The Avengers while inverting the formula. The real barrier to this one is the lack of (living) small-scale villains in the MCU at this time. Low-level threats like Moonstone, the Beetle and Songbird just haven't had the time to develop, or even cameo, and evil mastermind Zemo has yet to be introduced into Captain America's tale. This is a story, perhaps, better not rushed, and saved for Phase 4.