Approval Voting versus Instant Runoff Voting

If only we could use approval voting to vote for a new voting system. Free elections are not always fair.

Does Approval Voting really pass the "favourite betrayal criterion"?

There are scenarios where if you don't vote for both Good and Ideal, bad will win, and scenarios where if you do vote for both Good and Ideal, Good will win (over Ideal)

You obviously don't know which scenario you're in when you vote, so you don't know whether you should vote for both good+ideal or just ideal - both options can cause a worse result

I suppose the idea is that you use polling to decide which scenario is more likely and vote accordingly

As a libertarian anything that increases the ability of a 3rd party go gain traction interest me but something smells very off about the recent uptick in discussion of alternatives. If these changes were actually beneficial to the underdog in the general case you'd see them being pushed by the left or the right on a state by state basis depending on the political make up of any given state. The parties aren't run by idiots. They've crunched the numbers. They know whether the alternatives would benefit them or not. Likewise it makes me very uneasy that we mostly only see people who align with one party pushing for alternate systems.

I'm not opposed to alternate voting systems but I'd like to see one actually increase the power of the underdog(s) in a one party state (the only kind of state where the powers that be feel secure enough to make this kind of change) in the US before I support one. I don't want something that sounds good but furthers the status quo. Political diversity is one of the US's strengths and anything that furthers the status quo is bad for that.

Edit: why is this opinion unacceptable?

That's fixable by using voting machines to print the ballots. E.g. fill in the circles but also print the number of filled-in circles for each contest. Or, print only the selected candidate names.