If it's non-transferrable...

a) That +10 years after holder death no longer makes sense

b) Corporations would be unable to posses copyright.

I think intent is pretty clear and legal types could fairly easily turn it into precise enough legislation and find ways to prevent creative evasion.

a) Is a clear and simple exception, that permits inheritors to receive proceeds of a work for a limited time. It would prevent the abusive control some estates have over copyright decades after the creator's death.

b) Intent seems rather like the clauses for code copyright many of us have had in contracts of employment. IANAL but I'm sure something could be drafted that limits transfers but still allows design companies assigning copyright of the customer's new logo. Perhaps the only transfer can be limited to the first three months after creation or something.