Rk1 is definitely an interesting place, in the past 3+ years I've been in AO the pendulum has swung each and every possible way - just like it does in any game with a Side conflict situation like AO's.
When I just joined the game I think Omni was the ones with the 11+ Side %, but then for most of my mains life in the pre-SL days, Clan rarely dropped under double digits. FC does play Omni more than Clan, as a fact. Look at the SL launch. Omni quests were fixed way before the Clan ones were, allowing more Omnis to reach the higher ends of the Shadowlands before Clan. Thanks to some Clanners having no RL I suppose, Clan had the first 1-3 220s on rk1 I believe. I do remember Clan had the first for sure, Redemption doc and too lazy to look up the name.
Anyways, in the current state of affairs, Clan does have more experience. Not more players, more experience and committed people. Few Omni players have the drive to actually PvP and participate in NW like the Clanners do. Many more Omnis in the past 1.5yrs or so have ebayed more than Clan - at least from the ones I know. Look at Hells Heroes last summer. In like 2 weeks their average level dropped from 216 to maybe 204. So many of their higher officers quit/ebayed and they're nothing now. Thats just one example.
Numbers are not a factor. People love to whine about them. Next time you're running into a tower battle, do a !server to any org bot. See that the numbers are usually low 40%'s for both Omni and Clan, and 2-7% Neutral. Then you ask - why are there so many more clanners at the tower battles? Well, Clanners like to PvP. Plain and simple. Besides ShadowBreed Inc. and maybe Alphastrike, I dont really know of any omnis that would go out of their way to do anything to win a tower battle or gankfest. Its hard for the omnis to just get the people to fight. Omni has been losing forever, and when you're losing you don't want to fight because you think you're just going to lose. This doesn't go for everyone, but many people. Even though the side xp% isn't too drastically in favor of Clan, everything that matters does. High end NW (does Omni still have 0 200+ towers? been awhile if so), Tara, and many other things even APF the Clanners can usually push the Omnis around.
Its funny, in the words of Tiamin: "Playing rk2 Clan is like playing rk1 Omni, who would ever want to do such a thing?" It seems like the servers are the exact same, with the exception that they're just reversed in terms of who is dominant at what.
Maybe some great old Omni PvP leaders will come back someday and help the Omni cause, or some org or person will step up to actually make tower battles, PvP, and Tara more interesting. My opinion isn't really biased, since I've played all 3 sides extensively on both servers. Dont try flaming either, since I honestly wont care or probably wont look back at this post for awhile. I have multiple other forums to spam

Imatroxdoc, 188/12 Atrox Doctor, Omni, Squad Commander of Band of Little Brothers
Ruffixx, 136/13 Opifex Fixer, Omni, Unit Member of Obsidian Order
Former account open for now:
Imadoctor, 208/11 Solitus Doctor
Frieloc, 205/8 Soltius Adventurer
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