OK... I'm going to get a bit heretical around here. I hope I don't get pelted with too many eggs
I'm still using the extension lever I bought as a tuning student back in 1978. On very tight pins, that flex can be an advantage... if you know how to "play" it.
I use a technique on tight pins similar to what I think Jeff D. referred to as "pulsing" in one of his earlier posts on this forum.
On jumpy, overly tight pins on grands, I'll hold the lever close to or at the end, and pulse the hammer. In a deliberate, controlled fashion, you make moderate, rapid pulses in the direction you want to go. Even though it seems like the hammer is rotating too much, the shaft will flex and then unflex, ever so slightly slightly nudging the pin. Then, as a last step, you pull back slightly to untwist the pin. The flexing and unflexing of the shaft actually does a lot of the physical work. It also acts a a bit of a shock absorber.
Sometimes it takes a bit of experimentation to find the ideal tempo and amount of force... you sort of find the equivalent of the sweet spot. You get a feel as to how much the foot is moving and how much twist is still in the pin to correct in that last step.
Also, various pins may require you to hold the hammer closer to the tip for more direct control and less flex.
I don't know how this would work for other people, though. I've used only this one tuning lever for the last 33 years, so I'm very familiar with it. I'm also left-handed. It may not work well for right-handers.
Yes, I do also use other approaches as well... mostly slow pull.