User blog comment:James12708/Possibility of a Mass Effect 4/@comment-94.193.58.109-20120919140238/@comment-24174486-20120921205657

"If you failed to gather enough war resources or told star child to go frack himself (which lets be honest we all wanted to do), then the reapers would still be a threat."

Having a low Effective Military Strength does not prevent you from using the Crucible to stop the Reapers; it does result in damage throughout the galaxy, especially so if you choose Destroy. If you choose Refusal (which let's be honest is a completely stupid waste of everything you worked for), the epilogue includes a different Stargazer scene where it is said that the next cycle defeated the Reapers.

Personally, I want a new protagonist if they're making a new Mass Effect game, especially if it's kicking off a new series. Shepard was an awesome character, but their story is over. If anyone can top Shepard's story, it's definitely the same people who created Shepard.