I would like to answer this question without concentrating too much on polymorphism itself. Looking at this suggestion I immediately think back to the RISC vs. CISC argument. Basically, by adding the type designation with the hardware device we are leaning towards the RISC attitude of computing instructions; I say this because giving the CPU the type designation directly from the hardware device will decrease the computations of the CPU and allow it to do what it needs to do because the work has already been done on the side of the hardware.
While this would potentially be a good idea as one would argue that it would lessen the amount of errors potentially occurred, I do also see an increasing amount of error occurrence. The reason why I say this is by referring to the chapters read in the book by Brookshear (mentioned below) where (very abstract summary) it is stated that certain electric interference may alter the state of a bit which would potentially corrupt the data being stored or sent (Brookshear, 2009). The more we rely on outside components holding imperative data and having it transferred to and from components, the more we need to cater for the occurrence of errors. If the work remained in the CPU, it would only need to receive the “dumb” data from the devices and we would have less scope for errors coming from the hardware component.
Another issue I see with this is that there will be an increased size in the flow of data along the controllers and buses of the computer. The rate of transfer along the bus is more than likely far slower than the CPU’s required time to compute the instruction along with its types.
My final issue against this notion would be the financial feasibility. As increased programming would go into the hardware devices then increased complexity would go into the software developed for the control of the device and the costs would no doubt be increased as well.
With all that said, I think in an ideal world this idea would be good to share the load of the CPU.
References
Brookshear, J.G (2009) Computer Science: An Overview. 10th ed. China: Pearson Education Asia Ltd.