A lot of good discussion in those older threads (thanks for making the effort to dig out the links, Checkboard - we're all faced with the getting older problem, mate) along with a few not quite correct ideas.
However, as we always have newchums coming up through the ranks, there is a value in revisiting the discussions afresh from time to time. If we can get folks to speak up, we can see some good, and some not quite so good ideas arise which then can be tossed to and fro.
As observed in some of the linked posts, in times gone past we had probably a higher proportion of career instructors than we see nowadays and that had some benefits for the Industry and the newchums coming through the ranks. If I think back to my own early flying, all my instructors were as old as Methuselah and made my dear old daddy look to be a youngster. I picked up the benefits from those old chaps, of course. Chaps like Cec Randall, Stan Hone, Jack Blackwell, Russ Evans, Joe Somorjay, and a few others.
Certainly, we all have stories of less experienced instructors whose knowledge sometimes shows gaps. I recall a tale from a colleague who had to pick up a light aircraft endorsement and I/F renewal post 89. The instructor involved insisted that the "student" (who had a squillion hours on heavies) demonstrate Vmc on whatever lightie was involved. My colleague, being smarter than the average bear, simply held off on the rudder to achieve a higher than expected departure speed. The instructor just couldn't quite figure out what the story was ... "it always goes slower than that !"
One of the problems in respect of performance is that the design certification standards are not routinely in the province of the training operators and that can generate or perpetuate old wives' tales.
If someone else doesn't start a suitable thread, then I may have to gird my loins and do so myself ....