but only on the single engine, fixed gear fleet, not the multi-engine, retractable gear fleet
Well.... back in the early 80's I did my multi ride in a C 310R. After touchdown, I raised the flaps (it was a relatively short runway). The examiner told me I should not have done that, and docked me a few points off the ride. I explained that this was a specified procedure in the flight manual for the 310R, so it was okay to do. He conceded that it was specified on the flight manual, but was still not a good idea, for the obvious reasons. I have to agree with the human factors, and risk vs benefit aspects of making control selections during the ground roll.
I have to agree that obtaining the maximum stopping performance from your aircraft, after touchdown might include rasing the flaps. However, I doubt that most operations involve runway dimensions which demand this. Those who need to do this, probably already know they do!
A few years ago I picked up an MD500 helicopter from a base in Alaska, which I had been told also had a runway. As I walked to the helicopter, I asked another local pilot where the runway was. "this is it" was the reply. It was a hole in the trees so small, I'd think twice before crashing into it! I've been flying STOL equipped Cessnas for 25 years, and I would not have considered landing in there. It was okay for getting the helicopter out, I did not have to vertical out. Some operations are just different in Alaska!
There are many things which can be done in aircraft, which probably should not be done, without a really good reason, as the risks far outweigh any benefit. For general operations, this would be one of them....