dancers are buffer units. The provide a % of their attack and defense to other units. Personally i never understood the 2 soldiers strat. ANd i do have both max lvl katie and AW-ed jerome. Even before jerome's awakening , after i got him , i pretty much never got to field katie again. Like...the only map i remember using 2 soldiers was the spirits dailies. Other then that , i can't remember a map that required me to have 2 gold+ rarity soldiers. Hell , having another philys (or any silver rarity soldier in general/with reinforcements ability - min costed if possible) cc-ed might be better for cheap fast blocker to deploy.
Then again , that's just my own experience , so each to their own. Even if u decide to do as switch suggested , another soldier is not your priority now anyway. I would suggest raising your core team till all are level 50 at least