Any ACA complying plan is a gold plan, or at least solid silver. It's one of the law's biggest flaws.
I understand your misgivings concerning the new associations admitted, but the logic is sound. Almost any business is associated with a interstate or national group. For example, the American Dairy Association, The Bar Association, or the AFL-CIO. The employer is entitled to provide coverage through the footprint of the organization, not just through the insurers of the state where the business resides. This is big advantage in low population states. Allowing non complying plans to be offered will save a lot on premiums. Granted, it is at the expense of coverage, but an ACA compliant plan will always be an option. Just not the only option.
There will be kinks and problems, but this is a much more workable approach than ACA itself.
J