I think Romneycare at state level has an individual mandate. Presuming Supreme Court finds the individual mandate unconstitutional at the national level, Romney can’t have the Massachusetts state plan expanded to all 50 states.
The mandate is only viewed as a mandate if a “penalty” is imposed for noncompliance. If the “penalty” is changed to some sort of “tax,” then there is no mandate because the individual can choose to pay the tax rather than buy insurance.
Romneycare will replace Obamacare by using a tax rather than a penalty.