Much is being made of the fact that a number of individual insurance policies are being cancelled because they don't meet the ACA's minimum standards. But this is nothing new--policies are modified or cancelled all the time as regulatory standards change. Simplest example is auto liability insurance policies that have to be changed or cancelled when the state makes certain minimum levels of coverage mandatory.
One of the more interesting examples in employment law was the change Congress made regarding insurance coverage for women. In 1976 the Supreme Court addressed an insurance policy provided to its employees by General Electric. Among other things, it provided disability benefits to employees who couldn't work for medical reasons. Absences due to pregnancy, however, were not covered. The Court, while acknowledging that only women can become pregnant, nevertheless held that the policy was not discriminatory under Title VII of the Civil Rights Act. (the case is General Elec. Co. v. Gilbert, 429 U.S. 125, 97 S. Ct. 401, 50 L. Ed. 2d 343 (1976), and the opinion was by Rehnquist, which shouldn't surprise anyone who follows the history of the Court).
In 1978, Congress, incensed by the holding in Gilbert, added the Pregnancy Discrimination Act (PDA) to Title VII in 1978 to make it "clear that it is discriminatory to treat pregnancy-related conditions less favorably than other medical conditions," Newport News Shipbuilding & Dry Dock Co. v. EEOC, 462 U.S. 669, 684, 103 S. Ct. 2622, 77 L. Ed. 2d 89.
So after Title VII was amended by the PDA, a whole lot of employer-provided health insurance policies had to be changed, or scrapped, because they didn't meet the minimum standard of non-discrimination now required by an Act of Congress. While most employers simply accepted the additional costs and kept their policies, a few dropped insurance altogether, and this undoubtedly hurt some employees. It was necessary, however, to right a wrong.
I see little difference between these examples and the inadequate policies cancelled because they didn't meet ACA standards. No law can have 100% beneficial effects, and no adverse effects. All we can do is maximize the benefits and minimize the harms. But no one wants to go back to cheaper policies that don't cover pregnancy, and we shouldn't want to go back to policies which provide no meaningful benefits.