What makes a Cabinet position "important?"

In criticizing President Obama's record on Cabinet appointments, Jonathan Bernstein says this:

With John Kerry nominated for State, it also means all four of the most important cabinet positions will be male, at least as long as Eric Holder sticks around at Justice.

I assume the 4 he's referring to are the Secretaries of State, Defense, Justice and Treasury.

I know there is a lot of historical protocol assigned to Cabinet positions based on the order they were created. But does that mean that those that have been around longer are more important?

I hesitate to think about ranking these positions, but it sure does seem to me like the Secretary of Health and Human Services has and will play an enormously important role during this administration's implementation of Obamacare.

And I suppose that the Secretary of Energy is one of the more recent additions to the list - but in terms of issues we face today, could there be anything more important?

Its pretty typical of a patriarchal society to elevate things like foreign affairs and war above the "soft" issues of things like education and human services. So I'd propose to people like Bernstein that you take a minute to think about these kinds of assumptions before you go critiquing someone else's commitment to feminism.