I agree generally with the OP - in fact I've long subscribed to my own version of this theory too, not too dissimilar from what Nerys Ghemor
suggests above - an 'escape valve' for the emotions of all of the drones. 'Collective individuality' all rolled up in one body, if you will. It may not be what the writers intended but it works, I think.
I do also agree with the sentiment that the reason that she is generally credited for castrating the Borg is that the writers tried too hard to give her a 'personality.' Particularly on 'Voyager.' Or, contrarily, perhaps they slipped too easily into letting her be a mustache-twirler. I'm thinking particuarly of the way she behaved in 'Unimatrix Zero.'
"Off with their heads!"
Not verbatim, but close enough. Borg Queen, not Queen of Hearts.
But I think the notion of the Queen's personality as a manifestation of the personality of the collective as essentially a spoiled little girl who's used to getting what she wants is as good, plausible retcon explanation as any, and helps me ignore those few cringe-worthy moments.