I knew I included other for a reason.
Why not include them together though? Just curious.
Because the skills and fighting styles in Siege are completely different then Battle.
Siege has a lot of closed in spaces which favor different weapons and builds, and has more "clusterfuck" fighting which again favors different styles. In Siege you need to know how to fight in a very close tight group and avoid being ganked, where as Battle you need to be much more aware of Cavalry, archers are substantially more vulnerable, less surprised around corners, crushthrough has a much harder time operating, AGI builds are favored more and mini-duels happen far more often.
Tactics required are also radically different.
Take my 36/3 build, it always dominates on Siege, yet is a liability more often then not in Battle due to that terrible athletics and other such things.
Also, I am an elitist who thinks that getting kills in siege is substantially easier.