I guess that's my main point being "the fairest and least disruptive way to do it."
I understand your ideas on the disadvantages and agree with you that it is more expensive. For the second point, what if a new employee was told up front during the hiring process that they will not have a pension. I believe it adds a fairness element and counters the issue of different packages.
I'll add the mci/vz wireless managers have no pension, ... rather than raising them up they dropped 50k managers down because of present and future competitive pressures.
Now if it let's people keep their jobs and adds to job security along with more performace based incentives that are realistic it may be the lesser of two evils.