Nomura has stated that Aqua can be saved. Meaning what we saw at E3 with Aquanort was an alternate scene. Maybe if Aqua is saved it plays out like this:

 

Aqua is saved by Riku and Mickey before she's Norted, meaning no fight occurs and The Way To Dawn isn't broken. Aqua leads them directly to Ven's room in CO, skipping everything there, meaning Repliku doesn't happen. Roxas still comes back. With Aqua and Ven, it will be easier to find Terra as their hearts are connected, now we have Sora, Riku, Mickey, Aqua, Ven, Terra, and Roxas. (Like the beginning of DDD) Darkness fails.

 

 

Now, with Aquanort:

 

Riku and Mickey are... too late. They have to fight Aqua and the Way to Dawn breaks. They go to CO anyway, maybe Aqua "lets it slip" that he's there. They're unable to find Ven, but they do find Repliku. Roxas still comes back. We're ever so conveniently two lights short. This is where Kairi and Lea come into play. We have Sora, Riku, Kairi, Mickey, Roxas, Lea, and... Lingering Will. We don't know if Repliku can use a Keyblade.

 

Repliku existing could lead into even more alternates like one where he has a Keyblade or one where Xion comes back.

I have actually had a crazy idea...

 

What if in the final stage of the game (before the final battle) Sora somehow obtains temporarily the power of Kingdom Hearts and is able to rewrite history?
 

So we might live a story with different events based on actions which will lead for example to save or lose Aqua, but at the end we have the chance to live every possibility until we take the right-canon ending and we go to the final battle. Literally "Everything can be done"...

I have actually had a crazy idea...

 

What if in the final stage of the game (before the final battle) Sora somehow obtains temporarily the power of Kingdom Hearts and is able to rewrite history?

 

So we might live a story with different events based on actions which will lead for example to save or lose Aqua, but at the end we have the chance to live every possibility until we take the right-canon ending and we go to the final battle. Literally "Everything can be done"...

That would be awesome. It would be funny if you could end up with something like Jack Sparrow being a Keyblade wielder.

I thought about it, but the translation might actually be inaccurate. By “the player’s effort” Nomura probably meant that Aqua will be saved in the main storyline... if that’s the case, the “player’s effort” would just be to play the game.

 

The plot seems pretty straight forward to me right now.

- Sora goes rob Olympus Colosseum to regain his powers

- Sora travels many worlds to master the Power of Waking and restore the lost characters

- Lea and Kairi train to effectively use the Keyblade in battle (we don’t know how much they’ll be useful... I don’t see them becoming masters AKA guardians in so little time.)

- Riku and Mickey try to access the RoD in order to save Aqua

 

Obviously, this is the general plot that will probably get way more complicated during the game.

I thought about it, but the translation might actually be inaccurate. By “the player’s effort” Nomura probably meant that Aqua will be saved in the main storyline... if that’s the case, the “player’s effort” would just be to play the game.

 

The plot seems pretty straight forward to me right now.

- Sora goes rob Olympus Colosseum to regain his powers

- Sora travels many worlds to master the Power of Waking and restore the lost characters

- Lea and Kairi train to effectively use the Keyblade in battle (we don’t know how much they’ll be useful... I don’t see them becoming masters AKA guardians in so little time.)

- Riku and Mickey try to access the RoD in order to save Aqua

 

Obviously, this is the general plot that will probably get way more complicated during the game.

I suppose that could be right. I just find it fun to think about what could happen.