1) This is not worse than FPTP at all since they are the same in the case of two candidates and FPTP has horrible properties with multiple candiates (the condorcet loser can win the election). Ranked voting can use various methods (condorcet or hybrid) to make sure the winner is the condorcet winner or in the smith set but that adds complexity and no voting method has every desirable property (IRV does not always elect the condorcet winner). Approval voting also can elect the condorcet loser which seems like quite a bad property to me (particularly since this can be affected by strategic voting).
2) Any confusion is due to lack of familiarity and the additional information can be useful beyond determining the winner.
3) This is only true when hand counting a lot of votes (just because you don't want to do it multiple times). Portland just had an election with STV for council seats and IRV for Mayor and these elections were (when possible) called early. You can see the early results here:
4) From a quick Google Scholar search there are risk-limiting audit options for IRV that usually work with few ballots but in occasional worst cases can need a full recount. See Blom et al. Ballot-Polling Risk Limiting Audits for IRV Elections:
I agree with buzzy_hacker that proportional representation is the most important thing to aim for. The main advantage of IRV is that it is easy to understand for single winner elections if you use STV for proprotional representation (which seems like a good choice for the US to me). As far as I know Ireland only has the President (a ceremonial role) individually elected but the US has a bunch of individually elected positions so going directly to the Irish system would be a bigger change.
2) Any confusion is due to lack of familiarity and the additional information can be useful beyond determining the winner.
3) This is only true when hand counting a lot of votes (just because you don't want to do it multiple times). Portland just had an election with STV for council seats and IRV for Mayor and these elections were (when possible) called early. You can see the early results here:
https://rcvresults.multco.us/
4) From a quick Google Scholar search there are risk-limiting audit options for IRV that usually work with few ballots but in occasional worst cases can need a full recount. See Blom et al. Ballot-Polling Risk Limiting Audits for IRV Elections:
[PDF] https://www.researchgate.net/profile/Michelle-Blom-3/publica...
I agree with buzzy_hacker that proportional representation is the most important thing to aim for. The main advantage of IRV is that it is easy to understand for single winner elections if you use STV for proprotional representation (which seems like a good choice for the US to me). As far as I know Ireland only has the President (a ceremonial role) individually elected but the US has a bunch of individually elected positions so going directly to the Irish system would be a bigger change.