I agree and I don't understand why some people are drawn to to STV. Among its problems is the simple fact that it is complicated. By contrast, simple approval voting (given 50 candidates, vote as much as you want and the top 5 candidates will win) will produce results just as accurate, and the math is much simpler -- every voter can easily understand what is going on.
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.
STV is pretty awesome to follow though, speaking as an elections nerd. Figuring out where the transfers will go entertains me enormously every election here in Ireland.
This is the only reason to study STV, to look at the interesting patterns. Likewise, I'm fascinated by a knowledge-graph pattern (I'm not sure if it has a name) where we use something like k-means clustering to discover less popular candidates who belong to the same cluster of voters who voted for the top candidate. I think the results would deliver good government, in that it would surface the maximum number of non-extremist ideas. But I think the math is too complicated for most people to follow, and so I think it would lack legitimacy. So I don't bother recommending it, except as a thought experiment regarding alternate systems.
