Let's face it - the primary process has the upside that it potentially permits a candidate to come from outside of circle of famous people, perform some face to face politics, and win the nomination from presidency. They cause the problem that the first states have disproportionate influence and therefore receive disproportionate attention. In and of itself, this is an inseparable part of the upside of the primary process - the one fact causes the other. Where this becomes a problem is that the states individually decide when their primaries are and so their is a race to move the primaries earlier and earlier. This lengthens the campaign season, making it more expensive, obviating much of the advantage the system supposedly had in the first place.
How do we fix this? Suggestions have included national primaries, regional primaries, and kicking out the state legislatures and independent voters. These approaches have their strengths and weaknesses. There is a solution that addresses the issues of our system and still gives states the freedom to schedule their own primaries: permit states that schedule their primaries later to allocate more delegates.
When you get right down to it, there are only two solutions to the problem that don't throw out the advantages of having a drawn out primary process away - take away the states' ability to determine their own primary date entirely, or play with the delegate math to enforce some sanity. Trapper John's suggestion falls into the former category, and in a philosophical sense it is somewhat repugnant to my sensibilities that state and local governments entwined in party politics regardless of the number of parties involved - it still divides the parties into quasi-officially sanctioned parties and those that are not. Short term, though, I just don't see that there's the political will necessary to achieve such a disentanglement. It is much easier to play with the delegate math to offer states an inducement to arrange themselves into a sane calendar than to go after such deeply ingrained institutions.
The next natural question that arises is how, specifically, would one go about doing that? The simplest system that prevents clumping and controls the calendar that I can think of would be something akin to the following: no delegates may be awarded based on any process where votes are counted before, say, February. Then you divide the calendar up into periods of time - 2 weeks, 4 weeks, calendar months, etc. Any states that vote in the first period get the same number of baseline delegates that they do today. Every following period would have a pool of extra delegates assigned to it that will be divided up amongst the states that vote during that period. How to divide the delegates is an negotiable question, but I think that dividing them proportionately amongst the states prevents the possibility of calendar delegates totally overwhelming the population delegates in number and effect.
That's it. The calendar delegates should be divvied up in such a way to keep the primaries coming at a roughly even pace, and may even need to be adjusted to prevent backloading.
Amongst the benefits of this sort of system is that it would give states a strong disincentive to clumping because the more states clumped up the fewer calendar delegates they get to divide. What's more, states have explicit inducement to schedule their primary so that it lines up with as few states as possible to maximize their delegate count. In this system the states would even be encouraged to get together and negotiate a calendar explicitly beforehand. Wouldn't that be nice.
Naturally such a system must also be sold with moral justifications and not just technical advantages because it seems somewhat undemocratic to have vote allocation based on anything but by population. There are two justifications I can think of. The first is that this is just leveling out a presently lopsided situation by rewarding states that wait with more real influence to weigh against their loss in media influence and their loss of influence in the fundraising race. In other words, this is a way of making more votes count, and nothing could be more democratic than every person having an equal say even if things appear unequal on paper. What's more it can also be said that the states who wait longer to vote will have had more time to consider the candidates and will have also had the benefit of seeing them face victory and/or defeat. So, at least in theory, those voters will have access to more information making them capable of making a more sound judgement than those who vote first. Thus it is wise that the late voter's voice should hold some more weight than the early voter's.