Well, all that excitement after I went to bed. But, my take is that it's value depends entirely on whether the group of compromising senators thinks it's more fun to kick George Bush and Bill Frist around every now and then than it is to walk around the senate halls with a "kick me" sign on their own backs.
(It's a mistake to call them all "moderates" - a willingness to act independently of the Bush administration and Fristy Frist, preserve the power of the Senate relative to the executive, and not behave in a corrupt mannerr to change senate rules has little to do with whether or not one has "moderate" political views. We don't live in David Broder's world, no matter how much he thinks we do.)
I think Feingold's response is correct in principle -- you really can't be serious about making deals with people who think that a threat to play Calvinball is a reasonable part of the dealmaking process. But, the real test is whether these senators are, in the back room, more serious than their public pronouncements to their rabies-infected base.