I hate to repeat what so many others said, but it just rings true.
I haven't played it again, and like many others I have no desire to. Which is tragic, because there were so many scenes and stories that i loved and made me feel so much more invested in the game. Finding out more about the Geth, dealing with the Genophage, dealing with the Rachni queen and whether or not to sacrifice Arlach company. Bioware clearly knows how to wrap up story lines in satisfying ways.
But it all goes out the window at the end. It's confusing, because Bioware has done at least some exploration along the lines of marshaling forces and deciding how to use them before. For those that have played Dragon Age: Origins, you know that what decisions you make affected what armies you had access to at the end. In ME2 you had to actually make some tactical choices on who does what.
I expected all of that, just much more so. I envisioned a take back Earth campaign where you are assigning armies, your squadmates, making hard choices. I got none of that, and a bad ending.
That said, I love all but the end. And the MP is a brilliant addition that added so much more than I thought it would. Overall still a plus, I just have no desire to replay it.