Given that Diskwarrior doesn't seem to be coming up with a new version which covers SSDs, is there anything similar on the market which will help those of us who think our directories need looking at and tidying up?
DiskWarrior has no problems working with SSD's as long as they are formatted HFS+:
FAQ — ALSOFT
As has been mentioned, Apple hasn't released the full specifications for APFS, so NO ONE has been able to create a comprehensive third party hard drive repair utility for recent Macs using APFS (SSD OR rotating disk hard drive).
However, this may all be mostly moot. On a different discussion list for consultants it was noted that in recent years Apple's included Disk Utility/First Aid has become quite competent, and that very few folks ever need to resort to Disk Warrior anymore.
And in those very few instances where First Aid has failed and Disk Warrior seems warranted, Disk Warrior may still not be the best choice. You see, Disk Warrior is now $120. For $120 (or less) you can usually purchase a brand new replacement hard drive and clone your backup onto it, which is a better option than using Disk Warrior, because even though Disk Warrior may repair your damaged hard drive, once it has become so damaged that Disk Warrior was necessary to repair it, that drive becomes suspect with regard to its reliability.
I used to hear from folks all the time who needed and used Disk Warrior, and Disk Warrior pulled off a miraculous feat by resurrecting their hard drive. But those reports stopped years ago. I think that, at this point, Disk Warrior is an anachronism. Indeed, one of the very reasons for the existence of APFS is to ensure the integrity of your data more effectively than the outdated HFS+. APFS may sound the death kneel for Disk Warrior.
A ZFS developer’s analysis of the good and bad in Apple’s new APFS file system | Ars Technica