Huntsman was always overrated and never actually viable. His moderate stance makes him unacceptable to a very heavy percentage of Republican primary voters, and those RPVs who do want some moderation are more likely to pick Romney. Huntsman might have a hope of winning in a future cycle if Republicans reverse their rightward slide, but his odds of winning this cycle were always essentially zero and remain so.
This sounds like John Weaver is acting like Cardinal Richelieu. Huntsman won't get far if Weaver is no more than a media advisor. I got a sense the campaign manager quit out of frustration with Weaver...
http://www.ksl.com/