I had my biggest breakthroughs with skiing years ago when I got my first pair of Head Super Shapes. The feedback that I was getting in every turn was immediate and I knew instantly when I was getting the skis on edge from tipping. I know that pretty much everyone that has tried or owned the SS's (or skis with a similar turn radius) has had the exact same experience. Unfortunately for me, when I got my Head Slalom RD skis, I noticed a big difference between the RD's and the SS's. The biggest difference is that tail on the SS's that keeps you in the carve longer and does not want to release quickly. Because of this I stopped skiing my Super Shapes and because the Rd's can be a lot to handle all day, I was not skiing those that often, I gravatated to skis with a wider turn radius, and I was skiing Fischer Progressors annd Head IM 78 in the 177 length as my every day skis. These are both great skis, but now that I am back skiing a 12 meter TR ski everyday (the 2011 New Head Super Shapes, yes the best skis ever made!!), I can say unequivicably that slalom turn radius skis are essential to ski on regularly. My progress has soared in my last 12 skiing days (yes 4 of them were skiing with Harald, Diana and Max) in some part due to being back on a slaom turn radius ski.
You cannot duplicate the instant feedback that you get with these skis and because of this, ones learning jumps into hyperdrive and the muscle memory occurs much much faster.
This past weekend I skied the new SS's most of the time, but I would switch onto to some wider turn radius skis for a run or two each day. When I did this it was obvious to me how much they can slow the learning curve. Yes, you can carve wider straighter skis and on good ones you can get really good pop on the turns. But you have to be more patient with the skis and to carve them well we are talking about GS turns. There is nothing wrong with the GS turns, but they occur at higher speeds and momentum plays a big role. Hence it is easy to think you are tipping alot because at speed the skis are going on edge and the edges are locked into a carve. As well the ski engagement occurs at a much slower pace so your balance is not challenged nearly as much as when doing slalom turns. Ultra high level GS turns by WC racers and high level skiers are a different story, but because most are not at this level it is really a different discussion.
I think the correct progression is to learn doing edge locked slalom turns on slalom turn radius skis and to pefect this. When you can absolutely rock slalom turns with pop on every turn, then go to GS turns. On GS turns the focus should be on turns that cut and bite back into the hill, not that get progressively wider as one goes down a steep slope. If you can can't get the ski to bite back and carve back into the hill, then you should go back to slalom skis and work on this. When I thnk about doing GS turns, I think about trying to do Slalom turns on GS skis (Helluvaslier talks about this and practices it). Essentally I want to carve the tigtest arcs possible with the fastest transitions that I can possibly do on GS skis. The place to learn this and get the proper feedback to be able to pull it off on a widerTR ski is from ones work on Slaom TR skis. Fast, and wide GS turns at speed give a very false sense of accomplsihment. Yes, the skis are on edge but it requires little (other than rding the sidecut) to pull off these turns.
I know this is in the broken record category, but I am as thick as anyone on this forum. Since I seem to be need to be hit over the head several times, I figure I will try to save you all the pain. Harald has been saying it for years, get on a 64-68mm waisted ski with a tight turn radius and learn how to carve tight turns. Once you do this and master it you will be able to ski anything. Nothing could be more true!!