I'll take a different view of this, quickly. What body you create or how it is organized isn't necessarily the issue. I think the issue is what kind of teeth you give that body.
Look at the United States, let's say, and how congressional committees work there, and how effective they are at getting answers out of departmental representatives. Obviously, Congress has a lot more power than these bodies, but you get a much more clear and decisive answer, whereas in Canada I've seen several examples of departmental representatives coming to a committee—to this one or to the government operations committee—and they somewhat obfuscate the issue at hand that they're being asked about or don't provide the answers they should be required to.
For any oversight body, it's really about the ability for them to gain information, to have teeth and to provide repercussions for not answering in a straightforward way.