Well the original Core design was to have Machinist to have multiple Weapon Mods for different Core gameplay styles.
Remember the constant complaint about Machinist not having Unique GB design on each gun? Well Original Design Machinist was going to have Unqiue Weapon mod desgin for each gun in their Weapon Modification Mechanic with each Mod changing the Machinist to a certain Core Gameplay style. The first two weapon mod were going to be a Laser Sight Mod and a Grip Mod.
Sadly we will never know how these Mods would have changed the Machinist Gameplay wise since rush to release of 3.0 and issues with the original concept development got in the way forcing SE to give us the current Machinist we have now.