Hindsight is 20/20 but there are a few analysts out there saying that if this merger didn't happen, both co's could have gone belly up by now. Carly was hired in a period of time when both co's (and the tech sector in general) were struggling and costs needed to be cut. She was hired to specifically restructure HP and cut their costs. Carly did this somewhat successfully. (maybe not according to the stock price) HP's focus is now on growth and this is clearly not Carly's area of expertise.
Again, hindsight is 20/20...what would you have done in her situation. Both co's are still around so that in and of itself tells me that she was successful. The stock could of been worthless by now as opposed to being down 67%.