There isn't much optimism left here but I will try to inject what little sense and optimism I can into this thread, considering the leaked story draft is again, an early, rough, story draft.
You all *assume* Miranda will be relegated to a very minor and diminishing role in ME3 simply because the draft mentions we will be helping her save Oriana. Well I have a little thought that could, you know, be totally plausible as a possible plot direction with Miranda in ME3.
First off, lets take what we know from the story leak. Done. Second, let's take Casey Hudson's statement of "Miranda will have a large role in ME3." Done.
Now lets think for a second. All we know firsthand is that we need to help Miranda save Oriana. Okay, now if I am half as sane as I think I am, this sounds like a starting off point with Miranda in ME3, a "pickup" point if you will. Who has Oriana? Her father. Who is her father closely connected to? The Illusive Man. Who is hunting Shepard in ME3 besides the Reapers? The Illusive Man and Cerberus. Who resigned from Cerberus for not believing in "the ends justify the means and screw everyone else if it helps humanity"? Miranda.
When I think of the overall plot of ME3, I think Shepard and every other person wants to stop the Reapers. I also think Cerberus is a clear thorn in his side and Shepard realizes that he can't fight two wars. I certainly think Miranda trusts Shepard way more than The Illusive Man at this point, and Miranda clearly has a concern for Oriana because Oriana is the only family she will have left, that she can actually love.
You know what Shepard would love though? Certainly he wants to get Cerberus out of the way, but what is better than destroying Cerberus outright? Getting Cerberus to ally with himself and the rest of the galaxy. Miranda has nothing to fall back on except Oriana and Shepard since leaving Cerberus, and Miranda strikes me as the person that wants to be a successful operative and an aspiring leader, but also wants to have the chance to settle down with those she loves.
I have been dancing around the bush here, but all this has been food for thought for you guys. Now let me get straight to the point with as sharp a plot device as I can here. Not extremely detailed, but something to speculate on. A groundwork.
Shepard starts off with Miranda in ME3 (at whatever point) in helping her save Oriana from her father. This is likely to lead to an inevitable confrontation with her father somewhere along the line, and choices will likely have to be made in regards to Oriana (maybe not though who knows). Miranda's father has connections to TIM, and this confrontation with her father gives Shepard an amazing opportunity; to be able to track down TIM and stop him once and for all. Let's speculate for a second that, whatever happens, Oriana is saved, Miranda's father is stopped (in some way), and Shepard discovers the location of The Illusive Man and/or the main Cerberus headquarters. Naturally, I think Miranda would accompany Shepard to revisit TIM knowing full well Cerberus is trying to kill Shepard. Who knows, maybe after Miranda's resignation, TIM has had Cerberus hunting her too. Think on that for a minute while I continue.
So, the final premise is that Shepard and Miranda travel to The Illusive Man's base and cue huge battle en route to TIM signature office. I speculate there will be major decisions upon confronting TIM (possibly a boss fight too). Imagine this, a major choice regarding Miranda, The Illusive Man, and Cerberus. Shepard can do one of two things; Kill The Illusive Man, let Miranda take control of Cerberus and all it's assets and allow her to realign Cerberus with Shepard's cause to fight the Reapers (Paragon naturally), OR Shepard can spare The Illusive Man in exchange for leaving him in control of Cerberus while making TIM promise to stop hunting Shepard and start helping his cause, causing Miranda to become extremely upset and leave Shepard entirely (Renegade choice).
Depending on the major choice here, Miranda can become what she's always wanted to be; a leader for humanity's progression in the universe, while also retaining Oriana, the only family she has left to love (with the exception of Shepard if romanced). This allows for HUGE character growth on Miranda's part. Now, obviously the speculated Renegade choice could be the biggest downfall we see of Miranda. Possibly. Again this is all speculation and optimism, but it doesn't hurt right?
Now, I just sat down and calmly thought and wrote that out to you guys because I felt it to be an amazing plot prospect. It probably does have holes; that's expected if I just sat down and wrote it out on two cups of coffee. Hopefully some of you will like this possible plot direction. Hopefully I've instilled some optimism that wasn't there the past 24 hours. I don't know. But there you have it. Your thoughts on it would be appreciated at the least. Thank you for bearing with this undoubtedly long post