I've heard that same garbage all over Free Republic too. Constitutional Law is NOT Patent Law is NOT Estate Law is NOT Criminal Law. Areas of Practice are NOT interchangeable.
Hewitt would have been closer to correct at the beginning of the Republic. Now there are 200+ years of precedents set by prior Supreme Courts to be considered. They have to look at what effect any current decision will have on the caselaw that followed those precedents, and what the reasoning behind those earlier precedents was. I'm not married to stare decisis but I've got a lot of respect for it. It's kind of the antithesis of The Law of Unintended Consequences.
So...
Do you mean that Harriet could make a real contribution to the others on the bench since she would have expertise that they do not?