To much coffee

I am sure you can throw 53k of gearscore at most bosses and win, even if your group is high mixed damage type and redundant buffs, and half your team is non-dps.

There is not much flexibility in dual-specs for your group, just a ret paladin and a shadow priest.

If you augment your group with different classes, I predict a lot of twitch will occur within the Kill Shot and proc management area that will make those classes very low performers and bleed out the raid. Only so much twitch you can introduce before your raid is suffering a lot of DPS issues.