Ehh, id say its a composition issue. 3 melee? Thats the main prob imo. 10m is more about how you stack your raid than it is for 25m. Having 3 melee, seriously gimps you on Shannox. Time to start sittin players and bringin in the ranged. My raid comp is composed of 1 melee and 4 ranged. Melee isnt really that useful on this fight. Also as a rogue, you could start disarming traps when Shannox gets low to eliminate the need to move him when he hits 30%.
Burning Rageface with 1 ranged and you trying to will take a long time. Its just not your job to chase around a dog that is faster than you. This will drag the fight out longer then it should, burning healer mana, and widening the window for mistakes.