If you want to get to the meat of the video, just skip ahead to the 3-minute mark.
I'm tired of losing every AV as Horde. Here is a video that demonstrates how to go directly to the Dun Baldar Relief Station flag in four minutes from the start of an AV match, without confronting any other players, any NPCs, or even crossing the Dun Baldar bridge. I perform this act as a disc/holy priest with a non-epic mount.
Having the AV-specific DPS buffs that increase your avatar size is not necessary, although it helps the smaller undead model.
If Horde do this every game, we can win ten-minute AVs.
You can call this an exploit if you want. In my opinion, it's no more of an exploit than the trick alliance have of jumping over the outer wall of Frostwolf Keeping and running to our relief hut without fighting any NPCs or dealing with our towers.
In my opinion, this evens the playing field.
Here is an explanation of the technique: From the small pond just south of Dun Baldar, head northwest to the western wall of mountains. In the corner where the mounts abut the Dun Baldar area (loc 40, 20), there is a feature of the terrain that allows you to walk along a mountain wall onto a flat path that leads directly to the relief station. Walking along the slope of the mountain correctly takes a few tries, and in my opinion it's easier to do unmount. Tauren models should find it much easier than Undead models (just like with the old trick for getting into the north Dun Baldar bunker). I encourage you to watch the video to see how to get the proper approach angle. Tip: Don't try and force yourself to keep climbing upwards while you are moving along the slope, just go straight forward. If you find it difficult, you can practice during one of the endless stupid turtle AVs where allies take IB before horde takes SH and everyone decides to farm honor in our keep for two hours.
Good luck!
