"If you lose on all of those, then you're really looking bad," Pearson said.
And West Virginia lost on all three fronts this year. It only got about 60 percent of the way to its total enrollment target, Pearson said. And it has the worst mix of young adults in the country — just 19 percent of people who picked a plan through the state's exchange were young adults, who are presumed to be healthier and thus help keep premiums in check.
Completing the trifecta, there's only one insurance carrier — Blue Cross Blue Shield — in West Virginia's exchange.
Hawaii is another consensus pick, and some experts say the state might never be able to support its Obamacare exchange. Hawaii was near the bottom for total enrollment, signing up just 15 percent of its eligible population, and had the second-worst mix of young adults. The state's exchange also suffers from the fact that Hawaii had a low uninsurance rate to begin with — meaning there's a smaller pool of potential customers there, which makes the state less attractive to insurers.
"Hawaii looks problematic. They could have viability problems," said Larry Levitt, senior vice president for special initiatives at the Kaiser Family Foundation.
Levitt added another factor that could drive up some states' premiums: whether they went along with President Obama's decision to let insurers un-cancel certain plans that don't comply with the Affordable Care Act.
The consumers who are most likely to keep their once-canceled plans are people who got a good deal under the pre-Obamacare system — generally younger, healthier people who enjoyed low premiums and who make too much money to qualify for the health care law's subsidies. Letting them renew their noncompliant plans keeps a healthy population out of the exchanges.
"That's the one I hear most often from insurers, and I think that's right. It certainly is a factor," Levitt said.
Ohio and Arizona, both of which allowed plan extensions, are on Levitt's list of states to watch for big premium hikes. He and Pearson mentioned Iowa, which allowed a two-year extension for canceled plans and was the second-worst state at enrolling its eligible population.
Health care analysts are also keeping an eye on premiums in Maryland, Mississippi, New Mexico, and South Dakota, where officials had to beg and plead just to get one carrier into the state's private market.
It's impossible, though, to say with any certainty whether a particular state will see an above-average price increase next year.
Premiums reflect medical spending, not just the demographics of state markets, and quickening growth in health costs — which many analysts are expecting — could lead to double-digit premium hikes irrespective of Obamacare enrollment.
Some states' risk factors could also change. After seeing the results of a stronger-than-expected first year, insurers that initially sat out the exchanges are thinking about expanding their presence. Analysts expect UnitedHealthcare — a massive insurer with hardly any exchange presence in 2014 — to enter several new state markets next year.