The latest S40 was upgraded significantly, so I am not sure what they could add to it to make it better. I am not in that loop though so someone else can fully answer your question.
With that said, 1 thing I may suggest is going with a V20c. It may seem like too much bike, but if the 20 degree seat angle scares you, you can either add a bit of adhesive backed foam padding under your shoulders to increase the seat angle, or buy a Thor seat that I believe increases the angle by about 5 degrees. Going with the Thor seat will allow you to easily slip on a Radical Design seat bag that will turn your already fast V20c into a very fast light tourer. With a bit of DIY you can add under seat storage for gear or hydration. I did that and got a 6L bag behind my head, and a 6L backpack on my chest. I use the backpack for 2.5L of hydration but I can put anything in the backpack that'll fit. Also, I can put up to 4 hydration bottles under my seat if needed. That is 12L of stuff plus 4 hydration bottles, as well as the Moose pack under the seat for tools and a tube. I could add another hydration bottle under the boom near the handlebars, as well as a frame bag under the boom near the cranks. Oh, I almost forgot. The Scarab bag, which is what? 10L? Not very aero, but that thing holds quite a bit so you are looking at at least 20L of possible storage space, closer to 25L with the Radical Design bag instead of the teeny bag I use.
Overall, I don't think the V20 can match the S40's max capacity because you can add panniers to an S40. So if you plan on carrying more than 25L of gear then the S40 is the way to go. But if you travel lightly and want to ride soon then a V20c is quite capable.