“So all that would have to be thought through very carefully. Right now the path we think is the most favorable is the shuttle-derived, in part because that gives us the best work force transition issues.”

Griffin said using shuttle-derived launchers would help NASA retain the work force it needs to keep flying the space shuttle safely until the last orbiter in the fleet is retired at the end of the decade.
----------------

It's all about not disrupting the current bureaucracies and big company players. The goal should be to cut the required workforce, not keep them necessary. Only govt funded projects think in this manner. Private funded projects always seek efficiency. Public funded projects all seek guaranteed cash flows and huge maintenance costs that can be serviced by private companies with patronage of govt bureacrats.

I'm not qualified to say whether the design concepts with which NASA is toying are not the way to go, but the sentiment expressed above, makes me wonder about priorities.