Just my .02.
Designers, in general, are fine for research if they keep their mouths shut and just observe. I think that it is a rare breed that can facilitate a discussion, designers are rarely in that breed. Also, designers are excellent for solving problems, they are only OK for identifying problems.
While not applicable for consultants and can be applicable to embedded corporate researchers, quantity time is far superior to quality time. It takes time to build a relationship so that the information/data provided is good. And it takes time to find the right people to ask. Most potential research respondents aren’t worth the time or money.
As for CYA research, I would fire any of my researchers in a heart beat for wasting time. I honestly don’t understand this. There is no such thing as good or bad data. Sure, it’s great if your product is a hit, “good data”. If your product sucks, “bad data”, then kill the project. Yes, most companies don’t kill, but they are fools to dump resources into a hole. But that’s their problem. Anyone who purposely cuts a finger off at the table saw has no sympathy from me. A tool is only as good as you use it.