No one wants it to be expanded, they want it to be deleted and completely redone lol.
I think people want variety and expanding each of the three (and possibly adding a fourth happy ending) is the best way to tackle this mess.
But lets say they keep it at three and they expand off of them, If Shepard lives in the destroy ending and thats the quote unquote happy ending then fine - Shepard makes it back to earth (somehow, I don't even understand how hes alive, but if they can explain it to me in a way that doesn't insult my intellegence then ok.).
The Mass Relays are destroyed but the way the galaxy communicated (The web system, holograms and what have you) had nothing to do with them or the Mass Effect drives so in theory they could still communicate between systems (at least in the control and synthesis endings. . .maybe I'd buy it in the destroy ending, maybe)
If they give us the super happy ending where Shepard is banging Salrian and Krogan groupies till the liqour runs dry. . .hey, I'm down but if all they show us are the consequences of our actions through out the series, through out the galaxy, then hey - no complaints.
. . .Also, they have to have an ending where Shepard tells the star kid to shove it. Even if the galaxy is doomed and you know it is, the options presented to you all amount to what the Reapers had set out to do anyway - assimilate or destroy. You destroyed the galaxy by wiping out the relays and even in the Synthesis ending all you did was make everyone the same which is pretty much what the Reapers where doing by indoctrinating the various races - however that would in a lot of ways make it possible for that large fleet to stay in the sol system if the biogenetic make up of everything was friendly to all of the races. No food shortages and they could all live on almost any planet.
They should rethink the whole of the endings. . .they should, but they won't and they probably wont because they have umpteen art evangelizing game "journalists" who have a more direct line to them then we do through our forums and twitters. Even if there are more of us than them we can't call up a Casey Hudson at E3 and say "Hey, this is Garrnet Lee from Shacknews. . .can we have a drink and talk about the ME3 endings? I think you should keep them as they are."
We won't get exactly what we want but as long as they tighten up the bullshit plotholes I'll feel right as rain.