You can set up a link party with a Linkshark and and swapping your A/R for R/A. Otherwise, you can also let your A sub Medic, letting your Dancer be more focused on dances and Misting people to oblivion. Imperials are cool, but they would really benefit from a main R support, as she has no time to set up and refresh the element runes with her combos. Sub R for element I, or B for non-element.
Fortress's shield skills are better in the late game, with AOE skills reducing the viability of Taunt and your F getting access to HP boost and Rampart. Dancer sub pretty much makes her the best tank in the game.
Bushi are really good with sustained attacking. They also have access to elemental attacks if needed. They can also pretty much sustain themselves with maxed HP and TP recover per hit. Either sub L or N, L for Vanguard/Initiative and Swordbreaker, N for 2 attacks and Follow Trace, which is hilarious with Charge (Charge affects both attacks).