1. Have them all on the same day.
2. One week later, would have the convention.
3. All delegates pledged, no super delegates.
4. Limit debates to 3 before primaries; if a brokered convention, then one more after primaries.
5. Allow candidates to have as many two or three way debates as they want. Maybe, I'm not sure about this one, but would like to try this out, because it would've been great to see a Rand Paul vs Chris Christie debate without Donald Trump ruining everything.
Apply this to any party.