If an account gets "disabled" (which i'm fairly sure is another word for "banned" or "deleted" in PS) you're not able to take their names. This essentially means multiple names literally just aren't allowed in the game any more, i.e. Dio Brando. It'd be really nice if you made it so you can take the names of banned accounts. As always, it's perfectly fine if this gets rejected - just means I'll have to work even harder to find a new name!
Disabled means no one can log in - this happens for various reasons, such as rule-breakage, by request, etc.
Disabled names can be claimed, but only badgeholders, PS contributors, and global staff can do this, if they didn't originally own them.
This has already been suggested iirc & denied mostly because the person might want to come back, and also as a reward for contributors. (i may be wrong on that second one but that's what i've heard before, feel free to correct if i'm wrong.)
Unless something has changed, I doubt this will happen.