Nonsense. Less than 1% of the Milky Way was explored in our cycle, and we saw less than 1% of that 1%.
Andromeda offers nothing that the Milky Way does not already offer, while the Milky Way offers things that Andromeda can't.
Yeah, but traveling from two supposed opposites of the galaxy (Citadel & Omega) in a matter of five seconds didn't exactly help with the immersion, especially not when the same weapons, armor, vehicles, technology and species are present and both locations, ME2 really didn't handle scale very well.
Furthermore, pretty much every thematical aspect that made mass effect being mass effect is gone; The Reaper Cycle, the mystery of the Mass Relays and the Citadel, the Quarian exile, the Genophage, the tensions between the council and Terminus and Humanity as the galactic newcommers. Pretty much the only thing left at the end of ME3 that set Mass Effect apart from other science fiction series are the Aliens, you may as well ship them over to another galaxy and try something completely different, which is what Bioware is doing.