1) Mandatory Coverage: Everyone must buy a policy.
2) Government vouchers based on need. (Just as food stamps do for nutrition)
3) Private policies of four or five standardized types. A limited number of policy types greatly enhances price competition. Label them A-E and require that the insurers call them by that label.
4) No underwriting: If an insurer elects to sell a particular type of policy, the insurer must accept all applicants. Differences in price arr allowed based on geographic area. But--citizens can change policy types only once every 5 years (reducing the "hey-I've got a bad disease, I'm gonna go with the Cadillac policy now" syndrome)
5) All policies (of the 4 or 5 types) would cover preventative care that serves to reduce medical costs overall (Pap smears, immunizations, prenatal care, annual checkups, etc). Policies would differ by the co-pay amounts, private vs semi-private rooms, types of perscription drugs covered, degree of "doughnut-hole" that the insured would cover largely on his own, etc). All policies would feature catastrophic coverage based on the insured's household income--maybe all medical costs over 30% of income would be covered.
6) A government-run clearinghouse with with medical/consumer information. Provides info on customer satisfaction with various insurers by policy types, information on outcomes by procedures for various hospitals/centers, average out-of-pocket costs incurred by consumers in each state for each type of insurance, etc). This helps promote consumer knowledge and informed decisionmaking.
7) Individual purchase of medical care is allowed. Unlike some countries which prohibit individual purchase of medical care, it would be allowed in the US. In addition, if you want to purchase an additional medical policy to cover cosmetic surgery, experimental treatments, nursing home care, daily electroshock therapy, in-home aromatherapy, accupuncture, etc, that would be okay, too