I don't think a 'conventional victory' would break the plot of the game at all (what little, coherant 'plot' we have left anyway). The Crucible is started right at the beginning when everyone, even Shepard, believes that it's the only real hope they have. They say several times 'there's no way to win this conventionally'.
However, that's before any of the characters have any idea about what's actually out there for them to use against the reapers. No one thinks it's possible to broker peace between the quarians and the geth and secure the full cooperation of each, no one has the foggiest idea that Leviathans with the power to kill Reapers exist, no one knows (including us) what other stuff might be gained from other DLCs. Perhaps advanced Reaper tech from the stuff on Omega. Who knows? Leviathan kinda came out of nowhere (as in, no one was really expecting it) and delivered something which, on it's own, makes the idea of a conventional victory feasible. Imagine what other random stuff Bioware could come up with if they want to.
As for it invalidating the Cruicible plot, from an in-game perspective, that's also doesn't make sense. Imagine everyone knew about the Leviathan and all the other stuff. They're hardly going to go "Hey Shepard, we have the plans for a weapon that could win us the war here, but we're not going to build it because we completely trust in your ability to reason with million-year old monstrosities from the depths of the ocean, and we also think you can negotiate a peace between two species which have been at war for 300 years with no formal diplomatic training". Of course, regardless of how likely a conventional victory might seem, they're going to build the Crucible anyway. Even if a conventional victory is seen as a possibility, it would still be a slim possibility and they'd want to have a back-up plan.
I agree with the sentiment that if enough DLC comes out with enough new war assets, you should be able to turn the 'refuse' ending into a 'conventional victory' ending. It would require you to have done literally everything; get all the war assets and secure the help of all the races. it could even function like the Quarian-Geth conflict in as much as you have to have played the other games (plus all the ME3 DLC) to achieve it at all.
It doesn't invalidate the other endings. Are the 'bad endings' (as in, the ones you get when you have low EMS) invalidated by the fact that you can get better ones by having a higher EMS? Of course not, I can't see anyone arguing that they 'shouldn't be there' because better ones are attainable. Some people won't attain those better ones. Similarly, having an ending that doesn't involve pandering to some dumb AI and still lets you win doesn't invalidate the other ones. It would just be a higher-teir ending that requires more skill to achieve. I'd say it fits much better with the story than the existing endings; it would be the ultimate 'your decisions matter' ending since it would require you to have made decisions throughout the game, not just increase some arbitrary number.
All in all, I have no idea if Bioware would do this. I think it's a no-brainer; it expands the existing endings and gives people the 'suck it StarChild' ending they actually wanted without invalidating or replacing the existing endings. For people saying that it would render all other endings meaningless, just look at the precedants arleady set. We have the best solution for the quarian-geth conflict that 'invalidates' the others yet I don't see people whining because it's hard to achieve. We also have the secret, 'best' ending where Shepard lives but only if you pick destroy. By that logic, there's already a 'best' ending so adding another 'best' ending changes nothing.
Good day.
Modifié par Cheesesack, 30 août 2012 - 12:21 .