I think the inherent complexity of, e.g. environmental regulation is such that it's impossible to write them in a way that is both effective and straightforward

I think the inherent complexity of, e.g. environmental regulation is such that it's impossible to write them in a way that is both effective and straightforward enough to be widely understood, much less widely agreed on. Inflexibility also works against effectiveness in cases where the law must adjust rapidly to changing conditions. While the US hasn't implemented it terribly well, I think the executive agency model is potentially a good one.