I mean the added complexity of STAR compared to score. It irks me that it basically adds second election using different system, that happens to sneakily reuse the same ballot.

It's not a different system, it's the exact same algorithm. In both rounds it is argmax(sum(candidates)) (identical to FPTP btw) but the first round you take two elements instead of 1 and second round you use one hot vectors restricted to the top 2. That's it.

> From an algorithms perspective RCV is more complex.

Perhaps, but people aren't computers.

It's admittedly difficult to score this objectively, but I find RCV much easier to understand.

Much easier to understand from the voter perspective of the tallier perspective? From the voter perspective I find them fairly equivalent and both are frequently used in the everyday world (scoring might be even more considering 5 star reviews). But from a tallying perspective I think it is very hard to argue that RCV is substantially easier. Again, the score/approval algorithm is identical to the FPTP algorithm (which is trivial). It is simply argmax(sum(candidates)). Just sum the totals in an excel file and pick the largest number. I don't know a single person that has a hard time understanding this and I suspect if they did they would have an even harder time understanding how to tally RCV.

With STAR, it's harder to understand the affect of your vote.

RCV means: "I'd like this candidate, but if he can't win, I'll take this candidate instead." (And so on down the list of candidates.) Most people understand the concept of runoff elections. And, it's very very obvious that adding second and third choice candidates will never make your first choice less likely to win (on your individual ballot).

Under STAR, the effect of your ratings are less clear.

I think you're over complicating it in your head and that's making it difficult for you to see. You need a different perspective. Instead the perspective you need is that you rate each of the candidates and then put that into the system. The system will look at all the ratings and determine which has the highest agreeability as a whole. If you're too focused on your own individual "should" then maybe this is hard. You'll over think how you should play the strategy and game the system to make your preference dominate. But the entire point of cardinal systems is to take this out because we don't want people gaming the system. We just want to find people's preferences and elect candidates that are most representative of the people.

You're having a hard time figuring out "the effect of your vote" because the entire point is for you to not be able to game the system. Obviously no system is immune to strategies and there very much are some here. But they don't have huge effects on the whole election. I mean we don't want to violate the monotonicity criteria.