IRV/rank choice voting doesn't fix the problems. What we need is Score Voting (https://electology.org/score-voting). Consider:

Rank choice FAILS to eliminate the spoiler effect, it just moves it. Consider that IRV claims it to be okay for Bernie to run as Green (as he was offered by Jill Stein) without spoiler. Well, let's say 45% top choice Trump, 35% top choice Bernie, 20% top choice Hillary. Hillary gets eliminated, because her voters are centrists, her 20% is split 6% 2nd choice Trump, 14% 2nd choice Bernie. Boom, Trump wins even if all the Bernie voters had Hillary as their 2nd choice. The claim that it was safe for all the Bernie voters to vote for Bernie because they would get their votes moved to their 2nd choice otherwise is a LIE. You only get your votes moved to your 2nd choice in IRV if you do not come in 2nd place overall. If your candidate comes in 2nd, your votes are worthless.

Score (aka Range) voting has NONE of these problems: https://electology.org/score-voting