Top 10 units for a DEX Team (in no particular order).
Trafalgar Law: 9/10
Captain Ability: 2.5X ATK to DEX units.
Special: Keep DEX orbs and turn all other orbs into DEX, TND, or RCV.
HP: 2052. ATK: 1300. RCV: 370.
Law gives a powerful DEX boost and his special really helps with getting out DEX orbs and, in turn, deal out a ton more damage. No one does a better job at leading DEX orbs than Law.
Captain Ability: 2X ATK & 2X HP to DEX units.
Special: 15X DEX damage to all enemies.
HP: 2232. ATK: 1332. RCV: 144.
Zoro really falls behind with his weak special. Everything else, his stats and captain ability, are pretty stellar.