Personally I wish we had a single primary day nationwide. After the first 25 states have made their decision, candidates have dropped out who may have done well in later states.
The Founding Fathers knew what they were doing when they established the convention system for choosing the party's candidates. The problem of direct elections by the populace in the primaries as opposed to the elections by the delegates parallels the problems we would have if we switched to a popular vote, forsaking the electoral college.
At any rate, though, CLOSE OUR PRIMARY ELECTIONS!