Actually having gone through the ending a couple of times I now realise why everyone seems to be so pi55ed off with the ending. Its almost as if the ending was just put there to just get the game out. There're so many holes in the ending it seems a totally new writing team took over for the last 30 minutes.
*Spoiler time*
How can the mass relays be destroyed? In the DLC for ME2 it was pinted out that destroying a mass relay would destroy solar systems. Yet this doesn't happen when they all get desyroyed. Also how does everyone who was fighting the battle around Earth get home?
No clue is given to what happens after the battle except the Normandy crsh lands on some random planet. How did the Normandy get there if the Mass relays were destroyed?
There's a few more I've spotted but what really anoys me is that unlike the rest of ME 3 the choices you make in the previous games don't seem to matter as all the endings are pretty much identical. I know there's an ending where sheppard lives but even that is only a couple of seconds added on.
Its a shame because 99% of this game (and the other 2 games to be fair) is brilliant but its one of the worst written endings I've ever come accross in any form of media.