The newer style has been around for a couple of years now.
Like you, I wished they had changed it before I bought my system. So far I haven't read anything about Shopsmith swapping out the old ones for the newer one.
I think Incra still offers the older style for sale, and will need to retool the system so the newer positioner will work on a Shopsmith. That, and they probably won't change it until they run out of the older style they still have on the shelves for the Shopsmith.
Sawdust & Shavings,