If they don't have any dialogue, can't be interacted with in any way...maybe have some different selection/battle lines....why not just let us build our own hirelings like in DOS2?
I believe it's for ease of play. Creating a hireling is an involved and time consuming business. See PF: WotR for example. This is more casual-friendly.
I'm sure these hirelings come with a free respec so you can make them into anything you want if that is your preference.
