Wireframes are, ultimately, an IA’s way of saying “this is how content works on the site.” It’s the only real way we can communicate concepts and relations in a visual way.
But be careful. Developing IA wireframes is about determining message hierarchy and content interaction. It’s NOT about showing where every little thing goes. Because that’s what a designer does. (Psst: and, they do it a lot better.)
I’d worry about button placement. I’d worry about page hierarchy, what content needed to be emphasized, what needed to be on the left or right of the screen, what needed to be below the fold. I was putting lots of attention into details that didn’t address the strategic goals of the system.
I was doing the job of the visual designer and not as well as they’re able to.
The idea of integrating goals into the wireframes? The two- or three-phase wireframing process that gradually makes the shift from strategy to concept? This is so good. I’m stealing it for the methodology.