If you want to use some of the more potent spells then a time mage will help for their don't move spell, as well as for their ability to shorten charge times. The time mage class itself is not great, but time magic is very strong support.

Also if you want a dancer you need to have a female character get up to level 5 if I recall correctly in dragoon and geomancer. For a bard you need a male to do the same with orator and summoner.

Always have someone who can revive characters. You don't want your units to turn into a crystal because they will be gone forever if they do.