I rather like this system of recycling old mission fights for high level battles that you can farm for loot. I haven't been to the Kamlanaut or Ealdnarche rematches yet (I wanna build a party but haven't gotten around to it yet). I like the principle though. Here's a few potential targets:
-- Promyvion Dem, Holla, and Mea bosses.
-- Promyvion Vahzl fight as something you can do after clearing Dem, Holla, and Mea.
-- Promathia
-- Lilith
-- Gessho
-- Shadow Lord
Just a few off the top of my head.