Even though they are giving us a new galaxy, I still want to see more ME Milky Way pre-ME3 material, even if its just in the form of comics/book. They can do what the star wars franchise has done. Create material set in various eras.
Even with the Star Wars Episode 7 coming out, new stories set in the past of that galaxy are still being released. And before the Star Wars EU was wiped from continuity, the Knights of the Old Republic era was fleshed out a lot, giving us stories set thousands of years before the films.
Instead of just sticking to the future and just churning out Andromeda stories, they can jump back to before the recant invasion of Reapers in the Milky Way. They can create a parallel to giving us stories of humanity exploring Andromeda for the first time, while jumping back with earlier stories set in the early days of humans exploring the Milky Way galaxy.
Besides the possibility of showing us earlier conflicts such as the Krogran Rebellions (with Turians taking the place of humanity, so to speak), or even the Geth War (aka morning war), they could even show us more of the past cycles, specifically the Prothean one. Sure we know they eventually got wiped out by the Reapers, but there is more to that cycle then that. The Protheans (and their allies) after all won a galactic war against another machine race. A story set during that war would be great to see.