In my guilds kill I get two terror guards off, and we never came close to wiping, we only have two transition phases also. The immediate one from P1 to P2 and then one more, we completely ignore empowered adds and push the boss to Final Phase, then kill the adds we left up during his transition animation.
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.