I don't know either!; Though I agree it doesn't make sense, and it's on my "would be a nice thing to look at when time permits" list.; Insofar as I've looked at it already (pulled out the data and skimmed over it) I can see the extent to which it's different between classes, and also that higher level doesn't mean better buffs.; But, how to make it more standardized and a continuing improvement as levels increase, BUT still keep the class arts somewhat different from each other and not just have everything identical ... is something that will take some more pondering.
Fix progression but give the buffs different values between classes --> complaints one class has "better" buffs than another.
Make all buffs identical between all classes in values and progression --> complaints the crafting system is being dumbed down even further.
Leave the buffs exactly as is --> complaints they make no sense and aren't progressive.
Alternative D --> not yet percolated its way into my somewhat data-overloaded brain yet.;