Programming language theory has no concept of "correctly-" or "incorrectly-designed." It may show some properties of some languages, and researchers may express

Programming language theory has no concept of "correctly-" or "incorrectly-designed." It may show some properties of some languages, and researchers may express their opinion that they believe those properties are inadvisable for programmers. Programming language theory does not define a metric for what's good or bad, and, in fact, programmers are often (though not always) better judges of that than theorists.