I think a same-day regional approach is a decent idea. Like a very, very mini-super Tuesday.
At the very least, they should seriously consider having one state from each region on the same day.
Northeast: New Hampshire
South: South Carolina
Midwest: Iowa
West: Nevada
In the digital age, there's no need to have the early contests go one by one, the candidates can focus on multiple states while still having a personal touch and getting to interact with voters. If a lesser known candidate can't afford a 4-state strategy right out of the gate, they can go all in on one or two states, hoping to emerge as the surprise story.
Also make superdelegates contingent upon the use of primaries instead of caucuses, and upon following the above schedule.
Although I would make some changes.
For the midwest I'd pick Minnesota. It's not
as white as Iowa and has a major metro. It's not as expensive to campaign in as Chicago (no massive media market), and has a good mix of remaining white liberals and white rurals.
Michigan would be good too. Decent black population as well as a large suburban population as well.
For the west I'd pick either Nevada or New Mexico.
For the south I'd pick Georgia. It has a diverse population, a big urban area, lots of black and white rurals, and potentially is a Democratic state and well-representative of future Dem coalitions.
For the northeast, I think Rhode Island or Delaware could be good. Cheap states to campaign in but those which have diverse, urban populations and small enough so that candidates can actually campaign with the ability to make an impact. I'm biased of course but I'd LOVE to see Jersey go early. As a Dem electorate it's kinda not that different from PA or NY, with the caveat that we're more suburban. But for a populated major state, we go too late most often. The negative is that it's VERY expensive and is really just two metro areas.
These four regional contests can either happen on the same day, or take place earlier than the traditional cycle and happen a week or so apart.
Or we could do two on the same day a week apart. So like Feb 1 is the southern and midwestern primary and Feb 7 is the northeastern and western primary.