As technique practice goes I have been doing a LOT of shooting with my .22 lately and have noticed a huge difference in my shooting on my bigger guns as a result of it. I have noticed that a little error in technique on a rimfire shows up huge at 200 yrds. Since I have been practicing with the .22 I have also noticed I am getting far better with reading the wind, a little 40 grn round really gets knocked around a lot by the time it gets to 200 yrds. The other big advantage to practicing with the rimfire is cost. 500 rounds a day is not uncommon for me now and only spending 30 bucks to do it is a pretty big bonus.
I hear ya bman...I agree with everything you said.
Last year I invested in an old, clean Marlin heavy barrel bolt-action 22LR with a custom wood stock and the feel/fit and weight that would be similar to our hunting rifles; it was a deal I couldn't refuse.
My son and I use that to PRACTICE a lot of off-hand shooting and concentrate on technique from field positions for that purpose...The savings in ammo alone was worth it up-front. gun)