I run one dancer. Ideally, your defense teams should have two mythics and one duo unit (with a duo hindrance building), which really only leaves you three units that can possibly be dancers. If two of those are dancers, the rest of your units better be heavy-hitters (Thrasir, Bramimond, maybe Lif on the Mythic roster) and have good color and range coverage. I find it pretty hard to meet all the other criteria and have multiple dancers. At one point I had two dancers, but the AI never really used them well. I think Ground Orders (and to a lesser extent, Guidance and Aerobatics) is a lot better than a second dancer, but it’s a little difficult to squeeze a Flier into my setups. Other good options are L!Lucina and L!Chrom with their difficult-to-predict movement.