That’s similar to the original US model, except instead of the member state legislatures directly approving legislation, they appointed two proxies to the federal Senate. It’s a good system.

But being able to originate legislation in the directly elected legislature is important. Even the original U.S. constitutional design, which was quite anti-populist, made the directly elected House the main originator of legislation. (Either the House or Senate could do it, but only the House could introduce appropriations bills giving it primacy in the legislative process.)