GI is whatever the standard iq test measures. Higher numbers seem to correlate with better outcomes in certain settings. Right? What's controversial about that?
As I said before IQ is an indicator of potential at best (the potential for the abstractions built on top of it), even of the low level abilities it does not include all of them, we cannot externally measure all of them.
Here's another way of looking at it: if IQ _was_ comprehensive, the number of individual questions would be astronomical, it would be impossible to construct or take such a test because it tries to enumerate and quantify all of the different learned abstraction above the inherently low level ones across all of humanity.
Taking that fictitious test a bit further, note that if we imagine all humans actually taking it, their score will be extremely low, because it's impossible to have 100% (you would need a massive brain that could simultaneously learn all of the _different_ ways of thinking).
> GI is hard to define (true) and measure (not true?)
Doesn't this seem like a contradiction to you? how do you empirically measure something that you cannot define?
There is no correct definition, however most people agree that intelligence is more than innate ability. If you are focusing on the later as a definition then you can indeed measure it, but consider that there are many people with an IQ as high as Einstien's, but no such deep understanding in quantum mechanics or even any subject.
I would argue that casting out "learned" as something superficial is incorrect, learning is not simply acquisition of knowledge (as education systems have very slowly begun to understand since the mid 20th century)
"Great developer" Is extremely subjective from both perspectives. Specifically the role, what are you developing? but more importantly the person, clones are not useful in cognitively demanding roles (otherwise it would have been automated already).
Highly subjective things are messy and often impossible to quantify (as smallnamespace was arguing), but his analogies were weak in this respect so I furthered this argument by extending it into the familiar difficulties of defining and quantifying intelligence (also highly subjective by application and individual).