Whilst I agree descent planning where possible should be managed so flight at or near limitation speed is avoided, I fail to see what the problem is with making selection as long as it is below placard speed.
The wording in most operations manuals is normally along the lines of "not recommended" or "should be avoided". This is not the same as "Not permitted". If it was a airframe risk, or damage may occur, it would be forbidden. There are times and places where selection of flap 1/5 at 235 kts cannot be avoided. If Boeing, or airlines see it as such a risk, they should contact the provider of local ATS units and ask them to provide arrivals that are designed with different tolerances in mind.
Horgy