Just a thought, would there be a way to use a different worm gear on a casting reel to change the "default" wrapping behavior on retrieve? Maybe one with more of a spread to make the wraps wider, thus reducing dig if you have thin line on the reel? I don't really see any other advantage it would have other than that. But is it possible?

one of the older zillions did that I think.

Yes, it's possible with a Daiwa. People commonly use the faster level wind 'worm gear' in a couple of others to help line lay. 

you can do this on a few daiwa reels.  The worm gear from a sol/alphas can be changed i think it was with a pixy and the pe versions of the zillion came with a faster worm gear.  More might be out there but those two i am positive can be changed

You can always remove the line guide and spool it by hand like the saltwater guys do. 

Like others have said the worm gear from one of the older zillions. I've never done it but the tackle trap has a kit in stock with all the parts you need.