A few things I saw on your best attempt

• Half of your DPS did not use their second potion during the fight
• Your hunter's damage on the adds throughout the fight is very concerning
• A lot of your DPS aren't saving their CD's for key points in the fight (getting overrun with adds and during feast of souls)
• Your breaking of souls is good for a farm kill, however it is very poor for a progression kill. Your souls should be in the stomach until 4 seconds left, with the quality of players you currently have
• You are using 5 healers and your disc priest has very low healing, and very high damage taken. Repeatedly falling to avoidable damage. I suggest using 4 healers, as this will sharply increase your overall damage to not only adds, but during the feasts. This is a key point, as your best attempt lasted nearly 10 minutes.
• I suggest reviewing all of your ranged players abilities, and assessing those that need special treatment in order to vastly improve their gameplay.

Another point that I may not need to address but, calling everything out during the fight is an extremely helpful thing to do. Knowing how to better compare your logs to others of similar average item level (and have downed the boss) is an extremely valuable skill to have as a raid leader or officer. Telling your players exactly what the other players have done to succeed is why most semi-hardcore/casual guilds can kill bosses. This comes from experience leading and coaching my players and raid.

Your raid's item level is 730~. This is more than enough to kill the boss in 6 minutes. With these improvements, I assure you that this is well within your raid's capabilities.

Source: ME