One little thought about the post-credits ending bit:
The old dude tells the kid he can go to the stars one day. It kind of suggests that he just has to grow up, and the technology already exists. The bit I caught was the bit after that that 'anything he can imagine' will be there, because the 'galaxy has billions of stars.'
Does this suggest that possibly in the wake of the relay explosions the races were able to create more advanced technology allowed free travel among systems, rather than the limited Relay method of only visiting the system that the Reapers had nominated as Relay points?
To be honest... I didn't mind Shep dying, I'm all for heroic sacrifice and stuff. I would have liked to know about the crew afterwards, but mainly it just bothered me that the relays went boom.