Germany already has a number of restrictions on contracts with regular people (corporations and certain persons are expected to look out for themselves).

For example, phone sales can't be final at that time, there has to be a 14-day grace period starting from when the purchase agreement is accessible to both parties (IIRC). Mail-order vendors have to accept returns on most kinds of goods, by law not by convention. Warranties cannot be shorter than a specified limit. Apartment rental contracts cannot ban having children, and so on and so forth.

The restrictions are real, even if most of a typical contract is still free to design and write by the parties.

This suggested change isn't larger than many of those, or groundbreaking. It's just another one like those.