I'm not the OP, but I'm pretty sure there's a simple, uncontroversial answer here. They were an excellent idea at the time, allowing much more pipelining with t

I'm not the OP, but I'm pretty sure there's a simple, uncontroversial answer here. They were an excellent idea at the time, allowing much more pipelining with the microarchitecture design techniques in use back then. In the time since, the complexity of the instruction set has stopped being such a big deal.