We are a small shop, 16 employees, and ISO has been great. I wonder if the clunkiness comes into play when more is being done than is required. We have been very lean in our approach to ISO certification, if it isn't required we don't do it. Our manual went from 73 pages to 13.
To the questions asked, wouldn't those outside processes just be Approved Suppliers? I wouldn't think you'd need to force ISO on them unless your customer requires all your outside processes be done by ISO certified companies.