Lure Rust!

Detail?

I think it doesn't matter so much with quick reaction type lure fishing. (most guys fish this way)
Low light too, detail over profile and action ? again, I'd say no, even with slower presentations.

Gin clear cooler water, lures in suspension, bright light or full moon ?, maybe it does.

Full agreeance with that statement I reckon. A bit of rust on hooks, battered to death. In reverse, even the 'bloody' streaks on new lures to suggest a bleeding fish.... I don't think any of it really makes much of a difference to what the fish does with the lure. If they spied a lure in that much details then they'd actually notice the weird curly things coming from the bottom and wonder what the hell it was! It's silhouette certainly wouldn't be 'normal' and I'm sure they wouldn't think it was actually a fish!

While visually it may not make a difference, what about scent?......................

Rust (iron oxide), even to human beings can have a distinct 'smell'. There must be a possibility that a massively rusty hook will actually smell more like the metal it is - to a fish? Lures generally don't smell of fish, so in situ does the smell of a lure become more 'metallic' and off-putting (moreso than 'normal')?!... Fish like wrecks, but they don't eat them.