Interesting, but how would Ridley fit into this?

I changed my mind.

There is absolutely nothing wrong with playing around with scenarios in existing IPs. I mean, yes, it would make a strong new IP (maybe), but it would also be fine if it was a Metroid game. High-quality experimentation in Nintendo's established franchises often has great results (Majora's Mask).

Much as scenario experimentation has resulted in tremendous character development in that same franchise (namely Spirit Tracks)

Though if anything, "another Metroid on a spaceship" would've been worse in 04, as that would've been 2 years after Metroid Fusion, and not 8

Um, space stations were what Fusion and Other M took place on, not ships. Plus what it's suggesting would be so alien as to barely resemble them even in the interior.

Don't forget narrative justified upgrade nerfing.  People hated Adam for that.

As far as gameplay would go, the difference would merely amount to semantics, unless the ship were to convey her to different planets

Now there's an idea, come to think of it...

If the environment was really alien, like some of the Dark Aether spots and Tenple Sanctuary area in Prime 2, then the appearance of the game wouldn't bring up Fusion and Other M memories.

Plus I'm pretty sure technology would've just relegated us to dingy, gunmetal gray corridors. Some of the stuff on the doc sounds interesting, but if they wanted to do System Shock they should've just made a new IP.

Technology would not have, but time would have: if you read through all the proposal, one of the "benefits" is that they can recycle corridors, with only minor variations, and thus save enough time to help meet the one-year deadline.

It would have been impossible to get done correctly on the GC and the idea of getting it done within a year would have made it a pretty poor game. That being said, another reason why it probably didn't go forward at that point would have been it being so close to the last time Samus was on a spaceship/station was Metriod Fusion which came just around the time of the original Prime, with its own AI more or less telling the players what to do.

Oh well, imagine if it was released, sucked and cause a design change in a game like Portal so as to not be accused of ripping it off. Nightmare world people.