Since the author states that salaries in the public sector are higher than in the private sector, salaries, not pensions, should be examined. The goal should be equal total compensation, in both sectors, which the Treasury Board says is their principle.

"In a defined-benefit plan, the amount of benefit is unconditionally guaranteed, which is possible only if contribution rates are variable."

In a good actuarial calculation of future costs, there is an equal chance of a surplus as a deficit. 

Certainly there have been  years of high inflation  with high return on investment such as the 70s and 80s and now low inflation, low return on investment. A balancing act which must be a challenge to actuaries.  There is a tendency to stress the chance of deficit, such as in this article. 

There is an equal chance of a surplus. 

Certainly, because of the perception of the public service plan, a study would be most appropriate. But first, salaries.