Yeah, that does seem odd. I would think that surgeons who were that successful at stitching people back up would be able to do a neater job. Also, I would think the wounds would heal faster with less chance of infection. Maybe magic takes care of the healing and the infection and the stitches are only necessary to keep the parts in general proximity to each other, so the surgeons got in the habit of using a few large stitches instead of a lot of little ones because it's faster to do?
I mean, steampunk or no steampunk, a lot of this world has to be functioning on magic. I don't care how good your science is, it's not going to account for some of the stuff that happens.