I'm at my grandmother's house. She's a neuropsychologist and showed me her contribution to the IQ debate... from 1988. "The IQ has long ceased to be a useful scientific construct for organizing and describing our increasingly complex and sensitive behavioral observations." 
Her main argument is that by lumping many different abilities into a single score IQ obscures the pluralistic nature of human cognition. It makes it hard to judge the real strengths and limitations of the people being tested.
She details a bunch of reasons why IQ is not a useful concept, theoretically or practically. It is based on circular logic. ("Intelligence is what the tests of intelligence test," says E.G. Boring.) It doesn't capture the nuances of impairment in brain damaged patients, etc
The most interesting part to me is her history of how IQ became so popular. To muster hundreds thousands of young civilians in World War I, there was a need to quickly identify which recruits would benefit from specialist and technical training. They used early IQ tests.
The psychologists who conducted these tests combined performances from fifteen different subtests and branded them "intelligence tests," from which they derived a single "IQ-score." Army psychologists were the first to popularize the idea that intelligence could be measured.
The other historical factor was that psychology wanted to portray itself as a hard science at a time of the development of rigorous math-based methodologies. "Surely the IQ's mathematical properties... would be Psychology's passport into Science's big leagues."
IQ's history shows how the quest to measure intelligence is all about reinforcing hierarchies based on expertise, in society and in knowledge. To me that's as good a reason to reject it as anything.
(You can read the whole paper here! sci-hub.tw/10.1080/016886…)
