Caliban Displaying Shakespeare's Voice...?

I have a feeling that this is going to end up being a long post...I can't really get around it.

This first part is for Abby. Here is another passage that I found, in which Caliban seems to be the hero and Prospero is portrayed as the villain (however, this passage does not necessarily indicate that Caliban voice is actually representative of Shakespeare's voice):

Act 3, Scene 2
Lines 46-62 in my edition of the text
Several of Caliban's lines here certainly incriminate Prospero from seemingly seizing the island from right under his nose. For example:

"As I told thee before, I am subject
to a tyrant, a sorcerer, that by his cunning hath
cheated me of the island." (46-48)

"I say by sorcery he got this isle;
From me he got it. If thy Greatness will,
Revenge it on him, for I know thou dar'st,
But this thing dare not." (59-62).

However, now that I have finished reading the play, I am not entirely convinced that Caliban is speaking for Shakespeare throughout the text. First of all, Caliban's last action in the play is tidying up Prospero's cell before his master's departure. Prospero is the one returning home. Prospero is an old man (similar to Shakespeare at this point) who reflects on his age at several points during the play. Prospero also has a significant name (sounds a lot like "prosperous" to me), and he gives up his magic during Act 5 with an lengthy speech, in which he frees Ariel from his spiritual bondage to Prospero. I connect this scene to Shakespeare giving up his reigns, so to speak. Shakespeare is giving up art/writing, which can easily be related to magic and spirtual experiences.

Also, if we take the Epilogue as a verse that was actually written by Shakespeare, Prospero is asking for applause for Shakespeare. He is also asking the audience to forgive Shakespeare for "bewitching" their minds with his art (his plays). He's making a strong statement on art's ability to invade the mind (not always in a positive way).

I'm sure I will be able to discuss this a bit more thoroughly in class tomorrow...