I think you are making assumptions here: > effective measure of the things people typically expect from it once you get into average or above average scores.

I think you are making assumptions here: > effective measure of the things people typically expect from it once you get into average or above average scores. But I don't think that's what IQ is, it's just a measure of a type of assessment relative to other participants. Beyond that, there are strong correlations at various IQ levels on how people perceive certain spatial and logic questions/tasks. IQ does not measure your personality or job performance.