As Joe said, specific claims are usually more precise. An action or series of actions caused harm to a first nation. Generally speaking, they're more discrete issues, whereas in a comprehensive claim you're talking potentially about self-government. You're talking about lands, resource sharing, management, co-management, that sort of thing, so I think naturally those are going to be a little more complicated to deal with over time.
Evidence of meeting #75 for Indigenous and Northern Affairs in the 42nd Parliament, 1st session. (The original version is on Parliament’s site, as are the minutes.) The winning word was agreement.
A video is available from Parliament.