Huh? What if I have a 48 core AMD server? A fully CPU-bound load average of 48 would be great.

Load average can tell you if the system is under-used, but it can't tell you how the system is over-used.

I regularly have a few dual core systems spike to load averages of 50+ because of suboptimal NFS mounts. The NFS issue keeps processes waiting around with nothing to do for a while. Those processes are still counted towards the "load" even though they have no CPU activity (they are blocked on IO).