I do think that this might be an indicator that a second season is planned, though. We now only have three slots for unknown civs, and still need to hit five regions from V: Portugal, Italy, Maghreb, Assyria, western US. And with the Gauls, we also have less confirmation that the devs won't try to cram the Iroquois, Denmark, or Babylon up in crowded regions.
Tbh, I'm a tad disappointed. Neither Byzantium nor Gaul were civs I really wanted, and all they do is detract from the possibility of getting more African, Southeast Asian, or North American civs. People are complaining about all the Hellenic civs, but now I feel justified in complaining about too many Roman civs.

At the very least they could balance out the Gauls with Numidia at some point.
Meh. Such is the way of blockbuster titles: this DLC pack was not made for me.