I'm still level 37, Horde, so I can't speak much about the higher levels... but at least for now, the Alliance pop is waaaay lower than Horde.
I levelled in Vanilla in an Alliance favored server (very favored... their queues for BGs lasted for an hour) and the situation for us was pretty much the same as is for Alliance here right now...
My thoughts (long, dont read if you don't care :p):
- STV was the same gankfest, this time for horde ofc. I find funny when people start "omg 37 paladin near gromgol" and five fellow Hordies jump out to kill him... or when I see people complaining "STV is hell"... you don't know what is STV for the other guys, really

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- An ally mage 60 came to Nesingwary to help allies and was overwhelmed by all the hordies there. It was hillarious. So much pop imbalance xD.
- I've been ganked in STV, at least 5-6 times. Never by a single toon. That goes to the next point.
- People in general is coward. Neither allies nor horde attack people on unfavored conditions. No one likes dying. The "stfu noobs l2p" I've read makes me laugh :p. Be sincere with yourselves.
- At 60, ranking PvP will be easier for Allliance, and much funnier. It's perfectly natural they got together in premades, we did in our server all the time. With instaqueues, why risk losing?

- ok, we Hordies get to gank a 54 poor fella trying to quest, woohooooo. Who laughs last laughs the best :p. Allies, don't reroll, life at 60 will be awesome for you.
- I saw two twitch streams of hordies "pvping" and in both cases, very brave groups of 60s ganking people in Western Plaguelands. /golfclap guys.
- If I didnt like being undead for lore reasons so much, I would reroll Alliance right now

- PvP will be so funny there...