The first problem with IQ is that especially for high IQ persons, let's say 125+, it doesn't measure well what most people understand as general intelligence.

The second is that it reduces the information about one's intellect to one number. People have different strenghts in pattern recognition, high-level thinking, creativity, analytical thinking, speed etc.

BTW, my theory is that personality traits have significant influence on intelligence. For example:

1) how pleasurable is it to learn new things

2) how pleasurable is it to think about problems

3) perfectionsim