i wouldn't say flying mounts, but i think wrath killed world pvp. i don't know how it was on the other servers but in bc on my server, you could fly around for like 2 seconds and find a 70 to kill. you got to skettis, nagrand, or places like that. the only thing that wrath has, that is somewhat like halaa, is wg and thats every 2 hours, halaa was whenever the heck you feel like it. also northrend is bigger then outland so everyone is more spread out and you get less pvp.