Me, I think we would have had to go there after losing Curly in the waterway in order to get the best ending.
Probably there would have been a door in GrassTown that could only be reached with the Booster 2.0 leading down into it (GrassTown is the only place you have absolutely no reason to go back to after fighting the Core, and of course we've seen the first room leading into Wind Fortress uses the same tileset and enemies... not to mention how it requires extensive use of the booster to navigate).
We also find some Gaudi there, outside of the Labyrinth... maybe they were supposed to have escaped after Quote and Curly fought the Core?
It's hard to tell how exactly Curly could have ended up in the G-Cloning machine (what does the G stand for anyway?) or what that machine's doing there.
I'm guessing the Wind Fortress is where the Killer Robots were originally stationed (and again, this supports the connection to GrassTown given how we meet Malco there). Perhaps it would have been a surviving robot that put her in there (granted that would raise the question why the robot wasn't cloning itself already... maybe he could have been too damaged for that?), or perhaps it would have been left a mystery, like who was giving you hints in the waterway cabin or how Curly got into hell.
After saving Curly, two options would have been viable: either she would be missing her memory, and you'd have to go get the Ma Pignon after taking her somewhere safe, or she could have regained her full memory because of the incident.
It could well be that the Ma Pignon side quest was introduced after the Wind Fortress was scrapped. In fact it wouldn't surprise me given how peculiar it is to have a robot regain her memory by eating a mushroom.
So what do you guys think? Do you have your own theories as to how Wind Fortress would have fit into the game?
Edited by Duke Serkol, 27 January 2012 - 04:12 PM.