I was drawn to STV in the past because I liked the level of control it gave voters, having them expresses preferences over parties and candidates. But now I'm more inclined to agree that its too complicated.

I don't think that the approval voting scenario you suggest is good though. If I want to elect five candidates, I want 5 candidates that represent the diversity of the population. But it seems to me that your suggested method will elect 5 candidates of the largest voting bloc, not at all what we want.