I am guessing that Dreier is moved up because they want to make it clear they think it is temporary. If it was permanent they would promote all the underlings up one.
You don't, in a temporary situation, want to promote every lower person up one, and then move them back down.
My speculation is that DeLay is going to fight the indictment directly to get it dismissed, rather than defend it.
It was interesting that they said Blount could take over SOME of the duties -- further evidence of the temporary nature.
I am really kind of surprised they didn't give Blount the Majority Leader job...
Dreier is kind of a lightening rod sometimes...
I really don't care what they do though, if it is temporary.