I also love these guns, and many people would like to see them offered by Ruger again.
Frankly, I don't know why other gun manufacturers don't follow suite and make guns wth no sideplates, having the workings all inserted from below. So far, I think only Charter Arms (a pathetically underbuilt gun, IMO) has done it, but Ruger utilized the design to create a true medium-frame class of guns that it promply dropped to follow the lead of Smith & Wesson, which needed to go to a heavier gun to handle the powerful full throttle loads. Staying with the "Six" lineup, Ruger could have advertised a smaller, lighter gun that was just as strong as the new S&W line, but Ruger blew it. Now people are looking for smaller, lighter .357s and no one but Taurus is making them -- but Taurus is hampered by the old sideplate designs.
Bill Jordan wanted a smaller, lighter .357 in a true medium frame, so S&W made the 13/19/66 revolvers in a .38 Spc frame. But these were just .357s made on a .38 Spc frame, and they had longivity problems. At about the same time, Ruger introduced their "Six" line of revolvers. These were designed for the .357 round and were also conveniently offered in .38 Spc. They could go through tens of thosands of full magnum loads with no problem. So what did Ruger do? They made their guns bigger and heavier to follow Smith's lead! It was stupid, especially when they put the extra weight up front, making it tougher to pick up and stay on moving targets. The newer GP-100s also just weren't as good as Smith's 686s. Now they offered no real advantage over S&W at all. But that's what happens when you adopt a "catch-up" strategy when you don't need to.
In my view, you can't find a sweeter .357 in any barrel length than the "Six"series. The 6-inch was, and still is, one of the best camping, hunting and outdoor .357s ever made.