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

[Velhart]

Because you're thinking small.
Think of future classes/jobs. Are you going to align EVERY melee to STR? Because that's just sounds lazy as heck and boring.
It already feels bland as heck. They should mix it up and give classes/jobs a bit more personality as far as attributes go.

Yes, they should align every melee with STR. They should align every ranged DPS with DEX, and they should align every magic DPS with INT. Its simple and easy to understand and much more organized. Giving them different stats does not give it more personality. Only the abilities and play style alone give it personality, not what it's primary stat is.

Because it has been associated with Ninja in past Final Fantasy series to be honest its only right to implement a new stat.

Strength has been Ninja's primary stat in almost every FF game they have been in.