There Use to be a Way to just Jump on Top Of the alliance Base with a mount they added a invisible wall i don't know if this has been posted before but if you are even decent at wall jumping you can get on top of the base. From here you can range the horde when they come to fight at your base and be able to range them. Or if your a horde you can jump up here and be able to range allies.
Video
[ame=http://www.youtube.com/watch?v=NlTgPpH2hQM]YouTube - On Top Of Alliance Base In AV[/ame]
Didn't look like this was posted before using the new feature they added.