I have been wondering this for a while. Is the threshold for 2 bars of population equal for each faction or is reserved space in a campaign based on total faction population.
I have noticed some factions seem to have larger populations than others when pop-locked, and also some factions seem to generate more latency when in vicinity. This could be inaccurate perception, but to get as many players as you can into Cyrodiil you'd want to reserve space based on faction population instead of an equal distribution per faction.
Would love to hear an answer from anyone who knows beyond speculation.