isn't this the same kind of spurious tea leaf reading that led to Souter being nominated
No. Miers is not a Souter
"Harriet Miers isn't a Justice Souter pick, so don't be silly. It is a solid, B+ pick. The first President Bush didn't know David Souter, but trusted Chief of Staff Sunnunu and Senator Rudman. The first President Bush got burned badly because he trusted the enthusiams of others.
The second President Bush knows Harriet Miers, and knows her well. The White House Counsel is an unknown to most SCOTUS observors, but not to the president, who has seen her at work for great lengths of years and in very different situations, including as an advisor in wartime. Leonard Leo is very happy with the choice, which ought to be enough for most Conservatives"
Hugh Hewitt
http://www.freerepublic.com/focus/f-news/1495695/posts
Souter's nomination arose from H.W. Bush accepting the enthusiasm of others for a person he had no knowledge of.
This Bush at least knows exactly who he's nominating.
One difference, W. has worked CLOSELY with this person for YEARS. He must believe he knows her heart and mind pretty well.