Well, I raised a question much like this less than a year ago .
The usual sort of list discussion followed and the matter was dropped.
What I wanted was that if M and N are integers, and M^N can be
represented exactly, the exponentiation operator should do that.
You're going a step further and say: if it overflows, let it overflow.
I'm trying to think of a plausible use case and can't. If we had unsigned
integers, I could.