Champion on Gendarran Field Bug?
No, it’s not a bug or limited to Gendarren Fields. Champs are not worth fighting anywhere—unless you are fighting purely for sport. But, check out the latest blog post by Colin. Changes are coming to make fighting champs worth the effort.
Champions dont give you any XP, they are just same mobs as Veterans and ordinary ones. I think you missed something. There are Dynamic Events that occur anytime, anywhere. Sometimes these events include a task to kill a certain Champion, this is common in starting areas, and less common in other places. So I think when you thought you got much XP, like 10% or 12% of your lvl, from Champion, it was actually from Dynamic Event that required to kill that champion and rewarded with XP