I actually have a really good idea for a second trilogy that follows ME3.
The first game would be a reimagining the Odyssey, the Homerian epic, you know,in space. You'd be a soldier/engineer/space wizard (depending on class) trying to get home after the war, and you'd encounter figurative space sirens and space sea monsters and space sorceresses and space lotus eaters, etc. It's all stuff that would fit directly with what's already established in the Mass Effect universe.
You'd finally get back to the Sol System at the end of the first game, and find out that Cerberus is a criminal syndicate in control of the Sol System, with the remaining council forces vastly outnumbered. Cerberus could have access to alternate technologies that allow them to get supplies via FTL, and that your family is in some kind of slave camp on Mars or whatever. So the second game could just be like TAKEN, in space, where you have to brutally kick the ass of Cerberus scumbags from one end of the Sol System to the other to get your family back.
So then for the third game maybe you could use Cerberus time machine technology to go back and punch the people who wrote the ending for ME3 in the face.