> It just feels like I basically never want it to be a copy, but you do frequently want to modify the element you're iterating over.

Feels differently to me :)

> It actually pushes you to design things in ways you might otherwise not. E.g., instead of []X you'll have []* X just so it'll be easier to modify from inside a loop.

Never do that. Instead I use indexes when I actually want to access the element.

(Where I do do that is in maps, but not because of range, but because index-expressions over maps are not addressable)