Just a couple more additions, this will probably be the last for a while.
Ryu2, 3.5
Arc2, 3.0
Shadow, 3.0
Sasarai (With TER), 2.5
Worker 8, 2.0
Strago, 1.5
Spar 1.0
Ryu, Breath of Fire 2
Advantages: Tanky with decent healing and physicals. Dragons are overkill damage for a shot.
Disadvantages: Dragons use up all his AP. Doesn't actually -get- those until Floor 3 or so.
Arc, Arc the Lad 2
Advantages: Brings a lot of neat team skills such as Weak Enemy, Might Mind as well as healing.
Disadvantages: His level advantage peters off very quickly. Speed may also be an issue.
Shadow, Final Fantasy 6
Advantages: Fast with good damage in Shurikens and Skeans. Has other anti-physical abilities, too.
Disadvantages: Damage starts to drop off quickly. Sucks terribly against magic.
Sasarai, Suikoden 3 (With True Earth Rune)
Advantages: Neat mage with fast damage and healing. Also status healing and magic protection.
Disadvantages: Besides his charge times he's kind of slow and isn't very durable.
Worker 8, Final Fantasy Tactics
Advantages: IMMUNE TO MAGIC. ITD Damage on top of that. Counters help.
Disadvantages: IMMUNE TO MAGIC. Can't be healed or revived via magical means.
Strago, Final Fantasy 6
Advantages: Blue Magic has a lot of neat tricks. Starts with good damage that is also MT.
Disadvantages: The really good Blue Magic isn't for quite a while. Strago also has some durability and speed issues.
Spar, Breath of Fire 2
Advantages: Relatively durable healer with stat increasing and debuffing options. Also some status.
Disadvantages: Healing peters off very quickly and damage is never very good.