Stan Collender hasn't been won over:

The plan calls for a substantial reduction in federal employees.  A reduction in employees generally results in the government relying on more outside consultants to get the work done but, in addition to the recommended reductions-in-force, Bowles-Simpson also calls for a significant cuts in the use of contractors.

The combination of those two seems to indicate that the now smaller number of federal employees will have to do everything that was done before, that is, that they will have to be much more productive. But Bowles-Simpson also calls for a three-year freeze on federal employee salaries and that almost inevitably means an increasing number of federal workers will quit.   That will reduce rather than increase productivity as new and less experienced workers replace the more senior folks who will have left for greener pastures.

In other words, Bowles-Simpson projects substantial savings based on the expectation that a less experienced and much smaller federal workforce will be more productive and just as effective than the more experienced and larger workforce it replaces.  That makes absolutely no sense.