I always heard that the '59s were prized for their PAFs [0] and the aged mahogany, but I've only ever heard one on a record and never played one myself. We've come a long way since 1959 in terms of neck dimensions/radii and modern CNCs can carve out pretty much any shape, rather reliably. Seems weird to prize since Gibson necks are horrible. But hey, guitarists are weird people.
[0] https://en.wikipedia.org/wiki/PAF_(pickup)