Civ sizes are unbalanced

Using /civinfo you can see civ member counts. Frost Walkers - 474 Planes Walkeers - 279 Wind Runners - 737 Wind has almost TWICE as many members as Frost+Planes combined! I'm not sure how major/minor of a role civs are meant to play in this gamemode, but I do think ideally civs would be more balanced in terms of the number of members they attract. I'm not too sure if players find Wind more appealing for it's perks, or if players are biased to choose it due to the NPC being the middle of the 3. In the old Civ Facs there was a civ balancing system. If one civ had too many members relative to the others, new players couldn't join that civ. That kept civ sizes balanced, though I can also imagine players might find it frustrating if they couldn't join the civ they wanted, or especially if friends couldn't join the same civ. I'm not sure what the best solution to this is. If I do come up with ideas may make another suggestion.