Asininely large numbers are a bit of a Final Fantasy tradition. I don't mind them at all. WoW only needed to do it because their engine was limited (and the last boss of the expansion before the first squish had 3-4 health resets because player power was so high). If we run into the same issue, fine - squish. If not? Keep them getting bigger. FFXIV's stat improvements are also nowhere near the exponential rate of WoW.