When Samurai does eventually come around (and it will; it is a pretty popular job) it will be a Parry Tank (since we don't really have one).
Points to note:
* SAM has highest DPS possible between all tanks
* Has abilities to let it parry up to 75-80% of the dmg that would be taken
* Has counter-attack abilities (which aid it in its higher DPS than other tanks)
* Tends to focus on single target tanking more-so than PLD
* High HP value (higher than WAR) but not much self-health recovery (less than any other tank)

That is honestly how I think they would make that job (and the fact that they considered it means that they had to work something out like this)

As for a sword wielding DPS, it will probably be Red Mage. It will use small swords/rapiers (would be cool if it was a rapier/rod or rapier/dagger combo)
* Uses magic to imbue sword with the elements (self only)
* Uses magic to cast debuffs on monsters (single target only)
*Slow
*Poison
*Paralyze
*Sleep
*Petrify (works like a stun)
*Dia