So, now Monk/Dragoon have to compete with yet another class?

[Aegis]

Agility is a synonym for Dexterity. They both mean the same thing. Unless you are meaning something non-standard for AGI it would be kind of repetitive and pointless to add it in.

They aren't really: Dexterity means how adept someone is with their hands/feet. Agility is more related to litheness of body eg flexibility, reaction speed etc. They are both very related terms, but not exactly the same .

Eg: A billiards player can be dextrous but not agile and a high jumper can be agile without being dextrous.

In XI, agility was the ranged acc stat and also the evasion stat. Dex was the crit and melee accuracy stat.