I figure they probably needed to three heal due to tons of damage. Two of their healers were disc and fistweaver as well, which most likely means the dps requirement was fairly tight as well. May have been like Empress where the balance of outgoing damage on 10 vs. 25 was just way apart, or it may have been like Rag where the dps requirement was way apart (or conversely, Sinestra - except getting by with two dps healers and one regular healer instead of just two straight healers). Still, have to wait for the videos to see what the fight is truly like.
I'd like to hear from Paragon members if they can talk about what the dps requirements and healing requirements were like on 10 man, or the same from Method players about how tight dps/healing was on 25.