Actually, guess most didn't notice.
Dred pop much faster for elyos since server merged. The number of active elyos is 20% more then asmo since merge, but those elyos (I believe is same as in retail) doesnt like to go seige if they know they can't get a sure win. So during the initial stage, asmo and elyos number was more or less the same, seige was more balanced on both side.
Then things changed, elyos managed to get these ppl for seige and with each win, more of those elyos who don't go seige started going. so seige started to started to reflect the actual number difference. And as days goes more will leave cause they dont see a point to play with each push from elyos (same as what happened in retail server).
If things are same as retail, soon elyos who are bored with PVE will jump to Asmo side to "try" help but it just won't work without number. Elyos will be constantly complaining cross fraction PVP instance take too long or doesn't pop. Then when gelk comes, elyos will push for all 4 fort and.... Just think back to retail before merge and you will know how bad aion is if the numbers are not balanced.