That's not necessarily all that different from now. We have a two stage system. In the primary people with broadly similar platforms run against each other. The "third parties" are factions within the two major ones.

Those options exist, and it's a multi way election. Primaries receive far less attention but they are where the real work of democracy is done.

I believe people are hoping they can vote for a radical candidate and a mainstream candidate, on the off chance people will love the radical candidate if they just get on the general ballot. I'm not convinced that will ever happen, and such people will be not just disappointed, but continue to be convinced the system is rigged against them.