Well when you do Call to arms. This can be any Call to Arms such as 'Call to arms: Arathi Basin'.
You can get a little bit extra xp if you do the following.
Grab the quest at a low lvl. Complete the quest. BUT. Don't hand it in.
Every time you lvl the quest reward changes and you get more exp. honor and gold. So if you do this quest and don't wanna pvp for a while. Just hold off handing it in and you get a little bit extra depending on how many times you lvl. This might be working as intended but I don't know. Don't flame please.