I cannot see any arguement that promotes any kind of 'two tier' level of training. You either learn to fly - properly - or you do not. Why complicate things with "only use this amount of flap" blah blah? Good gracious! Take the Warrior situation as an example - it is widespread mainly because Hershey Bar winged Cherrytrees used slightly higher speeds AND you can dissapate energy more easily in them.
The use of lesser flap settings (as described by the neophyte instructor) probably makes up for the fact that full flap and a huge surfeit of speed makes it near impossible to land tidily. Therefore first principles are totally ignored and another 'wrong' is added.
Adding speed is also used - I feel - to homogeonise handling feel from take-off to touchdown. The aircraft never actually feels much different throughout the flight whereas a Warrior (qv) at 65kt feels a little porridgy compared to the same machine at 75kt. I've no idea why this practise has occurred but I'm convinced that this 'smoothing' of handing response is partially behind it.
Utter disregard of appropriate speeds - however they are rooted - are usually covered up by the 'adding some for safety' maxim. There is never a situation that might warrant adding a greater than 10 knot margin to an approach speed for any light aircraft. 20% of the stall speed.
Sadly, the instructor base in this country (don't hate me for saying this) is very badly off for experience. Reason: the self-improver route as was actually promotes the emptying of experience from light aviation instructing. Now we are in a similar position whereby instructing serves only as a waiting room prior to entering the airlines. Because of this woeful lack of experience and interest in the subject there is very little to build on during what are usually short and rather narrow instructing careers.
I have been told by a flying club that to give me any part time instructing would be 'taking jobs away from the new guys'. I can understand that but it would seen that there is a philanthropic rationale behind employing instructors. It's a shame really. I'd like a part-time instructing position!
I think that one way of dealing with 'excess speed' and other rumours and wives' tales is to allow more non-professional instructors.
Just my 3.5 eurocents' worth