I think implicit in your comment is that the New Deal must not actually be amazing because it turns out that it's likely unconstitutional but... how does that logically follow? It's not like the Constitution was handed down from the heavens as a flawless document.
It may be that the New Deal does contain many unconstitutional provisions, but also that that same legislature was in fact a net benefit for Americans.
It may be that the New Deal does contain many unconstitutional provisions, but also that that same legislature was in fact a net benefit for Americans.