How in in blazes do you know that she is a " Souter-In-A-Skirt"?
How do we know that she isn't? That is the point - why not nominate someone with a track record that is reviewable rather than someone with no track record at all.
Miers may seem like a gun wielding Christian lady (those are hardly qualifications for the court) but how do we how she will rule with actual cases are in front of her? We can never be 100% certain, but with a judicial track record, we could make more informed decision.
Actually, by definition she is a "Souter" since she is an "unknown quantity" as Jeff writes. It doesn't matter which way she eventually goes.