Mike,
I like what you bring up. I enjoy looking at the different styles each architect uses in their depictions. Take MacKenzie for example, his sketches are not accurate and most do not offer a third dimension (elevations) but each can easily be interpreted; they have character and grittiness - naturalness one might say. Ross's drawings are exactly that, professional sketches that include elevations. Thomas's illustrations are somewhere in between both AMacK and Ross in my opinion. Wethered & Simpson representations are unmistakable, especially with the accompanying perspective sketch that depicts more than the lackluster plans.
The one I wish I was able to see more of would be Robert Hunter, but from what I can assume, (and we know what assuming does...) MacKenzie did all illustrations on the collaborations.