Your key sentence is "This is not, however, the same as the FAE resulting in an average of more incorrect judgements in the real world.", but you provide no evidence that this is in fact not the case.

I've encountered no evidence that this is the case, either. All I've encountered in my research is a lot of artificial situations in which the FAE is deliberately manipulated to produce incorrect results - in which case, it produces incorrect results.

On the whole, do you think that people are ascribing actions to personalities not often enough, as opposed to too often?

Null. My position is that people are, on average, calibrated more-or-less correctly for the culture in which they grew up.