Comment 6 for bug 1903413

In addition to this, there's a question of whether DELETE-PACKAGE is allowed to cause all the defstructs and defclasses named by symbols (formerly) in that package to disappear.
Personally I'd like DELETE-PACKAGE to be a way to clean house, but it isn't. There's always the looming possibility of enumerating the descendants of T and finding all the types that have become named by uninterned symbols.