To make the ending really hit home, there needed to be this kid running through the grass with the Normandy, just like in one of the trailers of the game. Then the kid comes up over a grassy hill and you come country side of tomb stones with people infront of some of them. The kid run past all of the tombstones still playing around with the Normandy ship and then trips and falls over breaking the toy. As the camera pans on the broken Normandy ship, you see someone bend over to pick it up (this person will be whoever your Romance option was, and if no Romance, then it will be defaulted to Hackett. This person also has clearly aged 30 years).
As the little kid is trying to stand up, you see bits of tears coming out. The person picks up the pieces of the Normandy ship in their hands you see a glint of tear drops fall on the broken Normandy. The little kid takes the broken toy, the camera pans out ward and you see a tombstone marked differently than others. The N7 insignia is clearly present on the tombstone and the person bends down to place something (this item would be prevalent to the Romance option, ie Garrus would place a rifle down, Ashley/Kaiden would place their N7 tags, etc.) and as the person is standing up, you'll see a glimpse of the name "Shepard".
The person would than salute the tombstone and the little kid follows in as well placing the Normandy toy on the tombstone in a fashion where it looks unbroken and imitate the salute (the person would help make sure the salute is proper and then have a tearful smile towards the kid). In this moment you hear the words "You did it..." Depending on the Romance option, they may have a like bit of a quirk after it (I can see Jack saying "You did it, and I haven't been laid in 30 years you son of bitch."). The camera will slowly back out and you'll see fireworks go off and hear people of all races cheering. This is in commemoration of when the Reapers were destroyed/synthesized 30 years ago. In the background you'll see that the burial site is actually at the base of the now non-functioning Conduit and encompasses a much larger area than imagined (think along the idea of a city wide memorial).
As the camera pans outward to show the New London, it starts to climb upwards to space with the focus on London and it keeps backing out showing the fireworks all over Earth and keeps backing out even further showing the Alliance ships around Earth and further it backs out of our solar system and then to our galaxy and just as it goes beyond our galaxy the screen starts to fade to black and then the music cues for the credits.