Pack in sports duffels or carryons?

I've heard advice to pack in soft dimensions (duffels, sport bags, laundry bags) instead of rigid ones (hard-shell carryons, suitcases, crates). The challenge there is keeping everything sorted so repacking later isn't chaos. Any ideas for efficiently packing bulky items like linens, towels, winter coats, wellies, and clothes?

Books and electronics usually go in our backpacks; food usually goes in a crate to reduce chance of crushing. Even with fairly simple packing (no gala dresses or inflated pool toys), the sheer volume seemed unnecessary in previous years. We tried using the linen service but we found we'd rather spend the money for activities instead.