I personally see no reason to not run AD over KJC. I have plenty of time to always get 5-6 CB off during my DS, and movement is a none issue if you are ignoring weapons like we do in P2. So during the siphon up I Fel Flame Spam, and maybe once while moving from desecrate area. Seems extremely unnecessary to run KJC on the fight? May just depend on each guilds strategy though.