It seems rather cheap that destroy, the best option and what everything was building to, is made "bad" by the Geth/EDI sacrifice. Making destroy the official ending (and Bioware outright saying that any future with the franchise builds on that) with the others as more or less bonuses would have been fine.
Overall things like seeing the citadel being rebuilt, etc. is pretty rewarding there. Of course so is Shepard galactic Reaper overlord... (basically just Synthesis sucks and makes no sense despite authorial fiat saying it's the best...)
If the DLC rumors are true though, it could be that they are going to use that to build up to an alternative ending tied to all of the DLC packs:
Sounds like along with Take Back Omega, the Leviathan of Dis is a rogue Reaper and it sheds more light on the Catalyst's control of the Reapers and betrayal of its creator. It could possibly tie to further destroy ending tweaks where with all of the DLC you get an option such as destroying the Catalyst while letting Shepard live freeing the Reapers or somesuch and maybe even a retcon on synthesis to suggest that's what happens there as well.
Since it seems like one aspect they're trying to bring in is that basically the Reapers while having the collective consciousness of entire civilizations they are enslaved against their will to do the Catalyst's bidding.
. Anything but control ending! That just replaces kid catalyst with my Sheppard. I don't want another kid catalyst! Down with kid catalyst!
But, but, but...! :(
ETERNAL. INFINITE. IMMORTAL.
Once more, the only parallel I can draw to Synthesis is Bio-Metal and the Scions from Battlezone. Based on BZ lore and the ending cinematic, Synthesis appears to be incredibly well-developed bio-machinery, effectively cybernetics ingrained at the cellular level. Yes, yes. I'll bite and say that it's still hokey that SPACE MAGIC can so profoundly alter the life-code of all living things in the galaxy, but you take what you can get. (Anybody who's completely lost at my reference should at least skim some of this (http://www.bzcomplex.com/wiki/index.php?title=Battlezone_2). )
That said, I was overall very pleased with the extended endings. While I still don't 100% approve of the direction BioWare decided to take the Reapers (and the fact that I still like my pet ideas (http://www.hard-light.net/forums/index.php?topic=80224.msg1613446#msg1613446)), I have to give them credit for a) sticking with the ideas they had already committed, and b) developing what was present a lot more. The original ending simply felt incomplete. That feeling grated me far more than any of BioWare's narrative decisions.
Oh, also- Refusal definitely seems like a troll move on BioWare's part. Bravo, boys- bravo. Really. I *liked* that you could effectively get a "you lose" ending (though it's technically a deferred victory, but whatever).
And that's about all I've got to say on the matter. I'm always up to kick some asses in multi.