The ghost of Shakespeare must be glad to palm off part of the blame for the Henry VI plays… they’re not very good.
Oh, they definitely have their moments, especially Parts II and III with the character of Gloucester already displaying the malicious wit and devilry that will soon bear glorious fruit in Richard III. Besides it’s absolutely fascinating watching the young Shakespeare develop his art, at first following in the footsteps of the University Wits - Marlowe, Greene, Peele, Kyd, Lyly et al - then gradually finding his own voice and soaring beyond their reach, much to the fury of Robert Greene, who lambasted the young dramatist in print, calling him an ‘upstart crow beautified with our feathers, that with his ‘Tygers hart wrapt in a Players hyde’, supposes he is as well able to bombast out a blanke verse as the best of you: and being an absolute Iohannes fac totum, is in his owne conceit the onely Shake-scene in a countrey’. The tiger’s heart line is an adapted line of Shakespeare’s from the Henry VI plays (O tiger’s heart wrapped in a woman’s hide!). Greene just could not stomach the fact that a mere actor was taking on the university graduates at their own game and soundly beating them.
Even Shakespeare’s apprentice works - the early Histories, Taming of the Shrew, Titus Andronicus, Comedy of Errors, etc - contain much to surprise, delight and instruct.