But at this point it's you who insists on a convoluted explanation, when a natural explanation suggest itself. Why would someone who authored complex in logic and elaborately styled letters, and penned some of them, be unable to pen all of them for reasons other than poor vision?
But Galations itself admits he's not writing the letters. What's to make anyone think he's writing any of the other Paulean (sp?) letters. If the guy can't see, why don't we get some sort of statement like "my blindness gives me sight" or something. That'd be very much like Paul.
What we do get, is a lot of genius stuff, but no evidence the guy was physically writing any of it down.
Look, it doesn't make it any less important if if was dictated or written personally.