Given Valens was an Arian OTL, it probably won't have any noticeable effect. Arianism is today often presented as some kind of fundamental challenge to the rise of the Church (because the Athanasians saw it like that) or some love-and-rainbows alternative that was averted by evil priests. In reality, it was, as the famous Rebbeleben joke has it, dialectical materialism to historical materialism. The fudamentals stay the same, it's just different people getting the shitty end of thestick.