Joebuck,
I can't speak for Jim but to me, it's totally obvious why he used three point contact instead of four. Simply put, a three legged stool will sit solid on any surface. A four point will only sit solidly on a perfectly level surface. Last I looked, trees are kinda lumpy and curved.... :D If the steps had four feet, you could bet that 99% of the time, one of the feet would not be in contact with the tree. Then there is the weight difference that would come into play too.
I know what you mean about the steps sometimes twisting a bit but I usually only have that happen if I dont' have the tension right or if the bark is very deep grooved like say on a black locust. It also helps to make sure that the rope going around the tree is below the level of the top two feet before you cam it over. Makes for a stronger setup.
Ray, I have both the Stepps and rapid rails (Steel version) and while I admit they are faster to set up, they take up a lot more space and I can't get quite as high as I do with 12 steps. Of course, I seldom go very high but the point is I can if I need to due to terrain or something. What I've done a few times this past year is to take the rails and about 3 steps. The rails get me about the right hight but then I put up the stepps so that I have hand holds going to about shoulder hight as I'm standing on the platform. I'm not as agile as I used to be and I really like to have a good hand hold as I'm stepping on and off the treestand.