Actually, Contract is Antecedent and Predent to the State.
(Please advance a Theory of Governance which does not recognize the Theory of Contract as Antecedent).
Unconscionable contracts must be voidable simply because not all contracts are entered into after arms-length negotiations.
If you're referring to "youths", "incompetents", "invalids", and etc., you're arguing Hard Cases against Principle. Hard Cases make Bad Law.
Start at the Beginning. (Please advance a Theory of Governance which does not recognize the Theory of Contract as Antecedent)
Best, OP
Mea Culpa; proceed from my correction.
Well, that's asking a bit much. My theory of Contract is that contracts freely entered into are presumptively valid, but where there is a gross disparity in power or in benefit, the beneficiary party bears the burden of demonstrating that the contract is valid.