I sure NOT a landing gear engineer or even a Boeing driver. That said, there is clearly a problem. It may appear to be limited to the 73 series, but that is probably a function of their great numbers. Common sense suggests an issue with hydraulic valve control, perhaps similar to the rudder control problem the was found - and fixed a few years ago.
While aggressive use of the rudder may help at the instant of landing, rudder authority obviously decreases with declining speed. I don't know what other options those crews may have. Boeing's suggestion that the number of incidents suggest 'acceptable risk' is not satisfactory and the problem should be identified - and corrected - IMO. This must be a horrific experience for flight crews; after making a stable approach and a good landing, to discover that they cannot steer their airplane once rudder authority is gone.
Most earlier Boeing airplanes provided nose wheel steering control only at the left seat. Does anyone know of this issue has ever appeared on an aircraft that provides a steering tiller for both seats? It may be a place to begin the inquiry. And finally, the fine engineers at Boeing are not idiots! I suspect that under the convenient cover of proprietary engineering details, the already know the reason for this performance defect. Sadly, their corporate masters won't allow them to publish the details or to provide a physical correction. "It does not happen often and retrofitting the entire fleet is too expensive," is probably the line from the executive suite. Sad, but true. This nose wheel steering issue is not the first instance of such cheap behavior from Boeing; they resisted (paying for) the 73's rudder control issues for as long as possible, using
PR fluff to cover them while the engineers fixed the issue. I do not know, yet suspect, that Boeing already has a fix for this steering issue, but does not want to pay the hefty cost to retrofit the suspect fleet - or admit to a defect. Good company, great products and a typical, deny everything until proven otherwise corporate culture. Sad, but probably true.
At the end of the day, I'd guess that Boeing drivers are still better pilots than are AB drivers; Some degree of operation remains in their hands, not those silly computers. Blast away: I've always made it perfectly clear that I am NOT a transport class airplane driver and yes, I have very thick skin. Blast as will, but please do not loose sight of the original post's objective: Low speed steering.