What differentiates varied Aspirants by their role and design?

An Aspiring Sorcerer that chooses to equip a Mark (which has a loadout cost and a bonus/penalty) can use Undivided powers or ones specific to that god, so they can always still use Foul Regeneration, Warp Instability, and any other Undivided powers in the future.

Initially, Nurgle Aspirants will have access to close-range healing and poison application in order to support from the front. Slaaneshi debuff enemy targets and support friendlies in melee. Tzeentch Aspirants are more directly offensive with fire-related powers, and should be best either embedded in a ranged-focused squad or dropping HoTs on characters right before they enter a dangerous situation.