Every thing you do in the airplane is a technique, there is no real "right, or wrong" way to do anything, you can't apply a value judgment to something like flying. Flying doesn't care if you do things the "right way," or not, flying can kill you even when you do everything technically "right." There is no one technique that applies to every circumstance of takeoff, or one technique that can be used in every permutation of the cross-country pilotage, or one technique that can be applied to the myriad of ways to start an approach. Some techniques may result in outcomes that are less than favorable (e.g. stall, spin, crash, burn) others are neutral.
As for the MP over RPM, what does it possibly do to you? It doesn't make the airplane unsafe, and though I personally think there is no merit to "keeping the prop on top" within reasonable limts (e.g. 39"MP at 1700RPM may not be good for it if its not in the book) that "technique" allows someone who is not intimately familiar with the powersettings of the airplane to make a fairly accurate Wild Ass Guess. When I jumped into the Cherokee 6 for the first time, what do you think my powersetting for cruise was? 24 Squared, and guess what, that closely corresponds for book powersettings of 75% power. Nothing wrong with that.
Further, I've had enough with the concept of absolutes here. Under normal circumstances slow flight close to the ground should be avoided, however, when you need to do Aerial Bird Survey in the 172 with 40 degrees of flaps quite close to stall a couple hundred feet agl so that the government bird spotter can look for egrets or some BS, you do what you've got to do. Scud running is bad all the time right? Wrong, how else are you going to get into a place when the ice is too nasty in the clouds and the approaches don't go low enough? Not flying for 3-6 months out of the year isn't really an option. 1.2Vso for an approach speed works great for long runways, however, I wouldn't do that someplace really short. Vy works great for climbing in some SE aircraft, however when engine cooling, and ridiculously bad glide ratios come into play, it might be better to fly faster. Let me put it this way, what worked on monday, may not apply to what worked on tuesday, which in turn may not apply to what works on wednesday. Some standardized practices are great for minimizing safety hazards and promoting a culture of intelligent compliance, however as 91.3 puts it, there are no absolutes, and you can even blatantly break regs to safely get the bird on the ground in one peice, if that doesn't say something about the non-rigid nature of aviation I don't know what will.
/soapbox
