Tacticians drift a bit from the traditional Soldier and utilize books full of battle data to help boss their allies around and create advantageous positioning, a good Tactician is highly desired as they are extremely useful.
Strengths
Has an innate skill which grants the party a 10% increase on EXP Gains. It's a good class to help friends grind in Crazy Dungeons.
Works extremely well with Youkai, or a large party.
Massive support potential being able to buff your allies from all the way across the field.
Has a variety of spells that, also, use a variety of Elemental ATKs, so they're (sort of) good for any builds, as they will have one spell for each Elemental ATK you invested on.
Drawbacks
Is primarily a support class, and as such is not as viable in a 1v1 battle. Might depend on allies to fight anything, be them Youkai or other Players.
Gun users or anyone with multi-hits will destroy your Tactician Ranking with ease.
Their damage comes mainly from casting spells. A single innocent silence will be guaranteed to cripple their offensive capabilities.