The reason I posted this here is because I believe Democrats are in the majority and would have home court advantage.
As to unconstitutional, I believe it isn't and it would just take passing a law to get it going. But all States except with only one seat in the house would need to re- district. That's why it cannot be implemented immediately. But the law could mandate that.
Suggestion to your point 1. An organization, like the NCC in Philadelphia could be commissioned to conduct a survey of registered voters in each State to determine their priority of all political issues in order from most to least important. Candidates apply through the organization and those with best matches to the voters are placed on the ballot.
One way to save the Democracy is to get the voters involved. These candidates will have a website and a printed resume which is distributed to the electorate. The candidate explains how he proposes to solve these problems. Candidates may not debate with political candidates. And other than their resume and website there is no campaign or its cost. One does not have to be a millionaire to get on the ballot, all is needed the will to address most pressing issues. That's why I believe Democrats have the edge in this.
As to constitutionality, do you know there is no mention of parties in the Constiitution. Each candidate should weigh any proposal and give his vote accordingly, not what is dictated by the party. I believe party politics had not been contemplated under the Constitution.