The problem with a National Primary Day, even if each state allocated delegates individually, would be that the candidate with the highest name-ID would tend to win and candidates wouldn’t be able to build support organically. We can complain all we want about IA and NH, but the fact that they go first and second with nothing else on those days, and they are relatively small states, permit candidates to make their case directly to the voters.
Of course, there is nothing magical about IA and NH that couldn’t be replicated elsewhere if two other states went first and second a week apart. (Well, it couldn’t be replicated in CA or probably TX because of their size.) So I would not be opposed to having the first two (heck, the first four) states rotate, with a week off between 1, 2, 3 and 4.
While I like your idea of basing the number of GOP delegates on the number of GOP presidential voters per state—the current system kinda sorta tries to do something similar—I think that the states that go first (rotating) should be the ones that are the most competitive in presidential elections. There are two reasons for this. First, both parties should vote on the same day, not only because primaries cost the state time and money, but also because it reduces the number of people who invade another party’s primary. And second, we want to nominate a presidential candidate that can win the electoral college, so I am more interested in how popular he is in FL, OH, WI, etc. than in how much he can run up the score in more heavily GOP states such as WY or TN. By having battleground/swing states going first, it would work for both parties.
BTW, looking at the past two presidential elections, if I had to choose the key states that should go early in the process based on their competitiveness, both IA and NH would be in the top 15, along with FL, OH, WI, MN, MI, PA, NC, AZ, NV, GA, ME, CO and VA. IA swung from Obama to Trump, and NH was within the margin of fraud.
I think that ship has pretty much sailed. Trump had 100% name ID. Most likely rat nominees are Biden, Sanders, and at this point Bloomberg. In the digital age I don't know how much camping out in IHOPs in NH means anymore. Trump only did big rallys. If Bloomberg's strategy works it will blow the whole thing up.
But let's assume that's true, and that it's to our benefit to have such an 'organic' nominee rather than someone with high name ID prior to running.
I'm still not sure that outweighs people in the later voting states getting no real say on the nominee. Texas had no say in 2012 cause Romney put it away already (with less than 50% of the vote).
In any case the disorder of the current system bothers me, scattered dates, different rules in different states. Some states winner take all even with a tiny plurality. Pennsylvania with it's beauty contest and directly elected delegates some of which were unpledged. The rats actually do it better having it all be proportional.
Anyways my thought was, rather than a primary, to do a caucus run by the party, charge a buck or something to participate, that should help pay for it and also reduce democrat interference.
If a candidate cleared 50% (or 40% with a lead of at least 10%) they would get all the points from that state, if not it would split between the top few candidates.
This would end the relevance of convention delegates in choosing the nominee.
Directly basing it on the GOP vote would also encourage those state GOP's to turn out their vote. I know the current formula as you said "sorta" does something like that, I prefer doing things to sorta doing them. ;-D
Going off the last election, Texas would have the most points for 2020 (roughly 7.4% of the GOP vote was from Texas so if we had 1000 total points it would get 74), then Florida and then Cali, PA, OH, NY. Due to the tiny number of GOP votes DC would vote with Maryland. I excluded territories since they don't vote in the general but Puerto Rico could be worked in.
Top two in points go to a runoff, unless someone gets a majority in the first round.
Some kind of national qualification process for who makes the ballot, I'm not sure if Weld or Walsh would clear it ;-).
Anyway, just an idea.
You make some good points about wanting a nominee that plays well in competitive states.