That sounds more like STV. IRV is only for single winner elections. You can't get coalitions or anything like that from single winner elections. The 2 major parties would still dominate any single winner election under IRV.
I think it's still better than FPTP, and it does let third parties at least get some attention. But there are other, better, systems. IRV has been adopted in a few places in the US, and then abandoned shortly after. I think systems like approval voting have a better chance of catching on.
> You can't get coalitions or anything like that from single winner elections.
But you can get more third party candidates winning (in single winner districts), leading to coalitions within parliament, which is probably what the parent means.
The problem with IRV is demonstrated in more detail here: https://www.youtube.com/watch?v=7Q7rzqJ0YS8
I think it's still better than FPTP, and it does let third parties at least get some attention. But there are other, better, systems. IRV has been adopted in a few places in the US, and then abandoned shortly after. I think systems like approval voting have a better chance of catching on.