Uh...why would anyone ever want Shepard back? The ME trilogy came as close to making me hate my protagonist as is possible without making me ditch the whole thing before it was ended.
I agree (more or less) I think Shepard's story is done, and I am greatly looking forward to seeing what is next. Sadly there are a lot of people who want the same story over and over again and don't want anything to change, so they want Shepard to return again and have the same story as ME1, 2, & 3:
Step 1) No-one belives him
Step 2) He proves there is evil in the galaxy! (Saren at the Citadel, Collectors on that Alliance world were we meet old squad mates, Cerberus at the Galaxy Leaders meeting)
Step 3) He collects something to win! (Conduit Info and Location in ME, Squaddies in ME2, Alliances in ME3)
Step 4) He defies all odds and defeats evil!
I'm saying MEs story has been bad, I've thoroughly enjoyed it. But I am very much looking forward to a new character and hopefully a new story archetype. Hopefully we aren't a soldier this time around. I am fine with where they left Shepard, maybe in 2 or 3 games they can have the ME Keep recognize your ME3 choices and build off what happens post ME3 ending, but for now I just want to go where no ME has gone before.