Good for you, Patrick. I followed the same thinking as you. I also lost Miranda, but it just felt like it would be wrong to go back and get the best ending, especially knowing that the story wasn't complete. If ME2 were the end of the story, I might have considered it, but it just felt like these were the consequences I had to live with to the end of the series.
When I finished ME2, I really wanted to play it again, but I didn't want to tarnish the experience until it was complete. When I'm done with ME3, I might play the whole series again, but I know it won't be as compelling as this first, incredible experience has been.