I have seen some of the s4 rods on closeout, so I assume they are discontinuing them.
As far as their 10′ rods, I picked up a 10′ 4 weight S4 last summer and have loved it for nymphing. Good with dries and streamers too, but I mostly use it for nymphing. Love the roll casting ability the 10′ rod gives. I don’t think I would want a 5 or 6 weight, would just be a bit much. The 4# has handled plenty of 20″ fish very well. I even use a 6# line on it sometimes when nymphing.
One thing I did have to do was get a heavier reel to balance out the long length. Overall a great rod, although I should disclose that picked it up on ebay from a fly shop that was blowing out their inventory, and I only paid $375 new.