I mean, if we’re dreaming that big, I would also kill plurality voting, electoral college, and fix senate representativeness? Though I’m not 100% sure I understand your argument that the Senate/presidency necessarily results in two parties? I read your link and I’m not seeing the connection.

My point is that the senate and presidency will always be essentially “single member district” elections, so even if you fix the House, the overriding incentives to win Senate + presidential elections will push towards two party competition. And, even fixing PR in the house is nearly impossible.