Trouble is, when Republicans do choose to talk about economic issues other than the terribly high taxes on “job creators” or the horrendous burden on businesses of anti-discrimination laws or environmental regulations or collective bargaining rights, they tend to adapt the same old agenda to the newly defined problem. So if there is a consensus the GOP needs a message on upward mobility, don’t be surprised if we are told yet again that what po’ folks need is liberty from dependence on government, and what middle-class folks need is for their employers to have an easier time doing exactly whatever it is they want to do.
I think that the notion of populism is (ahem) popular among the pundit class because it plays into their collective fantasy of a vast and under-represented centrist majority within the electorate.
The appeal of populism as a political concept is that it sounds like something that is shared across political divides. Republicans and Democrats alike will, when asked in general terms, shake their fists and rant about the fat cats in DC lining their pockets and ignoring the will of the people and the plight of the little guy.
The problem with populism as a political concept is that, once you start to scratch the extraordinarily thin veneer of the analysis above, it more or less falls apart. "The will of the people," while it sounds noble, is impossible to pin down. Alternately, it is terribly uninformed and frightening. When pressed on their actual beliefs, the same people will fall back on traditional party positions.