I'd argue FDR was a populist. It just depends on what kind of populism and to what end.

You don't get modern discontent and populism (and the current president) without the expansive (at the expense of congress and the states) executive branch. You don't get the expansive executive branch without 1930s populists and FDR.

Obviously there's a lot more nuance and detail to it (the blame Nixon deserves being of specific note IMO) but the argument is there.

So I'd argue that both the means are bad and the end