Strategy consulting isn't necessarily a bad idea right now. Sure, it's pretty clear that expenses need to be reduced. But how and where? To figure out what you should be doing, you have to know where you are and specifically where you want to be. McKinsey will help figure out where they want to get to. Only then can they formulate a plan on how to get there.
Having worked side by side with McKinsey consultants, their conclusions and recommendations aren't exactly revolutionary. After all, many of their recommendations come from employee interviews and well-known business models. But they're capable and have their own methodology which puts everything in a structure that can be explained and defended.
However, they serve several other purposes...1) they are less likely to have their own agenda in making recommendations (vs. employees); 2)since they are outside consultants, if their recommendations don't work, management can lay the blame on the consultants; and 3)Nobody ever got fired for hiring McKinsey.