First, Nippon has not increased the price of the shafts we carry by $10.00. KBS has had a substantial increase, but not Nippon. As far as the trajectory goes, the loft is what drives it primarily, with shaft dynamics having much less of an influence. With the stronger lofts, it does take some experimenting with head (loft) / shaft combinations to find the trajectory window you’re looking for. In theory, if you are looking at the trajectory of a modern #5 iron and comparing it to a traditional lofted #5 iron, you would most likely need to go to a different type of shaft to make the modern lofted #5 iron hit the same launch window as the traditional lofted #5 iron. If you compare modern lofted #5 iron to the traditional lofted #4 or #3 iron (whichever has the most similar loft), then the trajectory window might be more similar, but you most likely you would hit the traditional lofted #3 or #4 longer because of the length of the club. That’s the 3rd element of the equation, the club length. I do think that well designed modern lofted irons that have the actual vertical cg in a good place (lower and centered), will present a trajectory window that might be slightly closer to the traditional higher lofted options that may have had a higher actual vertical cg. It all depends on the designs. That being said, the cg has much less an influence on the trajectory in an iron than the loft. Definitely has an effect on the feel, but a minor effect on the trajectory. The loft is the main factor.
Personally, I think you just have to come up with the combination of head and lofts that, with the right choice of shaft, gives you the launch and trajectory YOU prefer.