Battlefield 4: Universal Soldier Aiming.
One of the many flaws of The Division's gunplay was all over the place zoom levels of weapons and wildly inconsistent, handpicked sensitivities that varied from weapon to weapon, while the person responsible for these mechanics hopefully meant no harm, and focused on "what made sense" and "felt good" the effect was ultimately detrimental to everyone but the most casual of players as it sacrificed consistency of controls for nothing in particular.
As such, I implore you to:
Zoom level should be tied to the optic attachment used, not the weapon category. The sight should only take effect (in terms of zoom and sensitivity) only when it's used, not when the weapon is raised to fire.
Relative sensitivity between zoom levels should remain constant, just like it makes no sense whatsoever for two sights of the same zoom to have completely different sensitivities, it's a huge quality of life to retain the same relative sensitivity (input to screen distance, read BF4:USA above) regardless of zoom level. The advantages are numerous, consistency is paramount, there's no downside to the implementation.
On a tangent:
Pay more attention to weapon balance so we aren't stuck in the state where overwhelming majority of weapons are completely unable to compete regardless of talents and don't butcher hipfire, "chickendance meta" was a product of bulletproof bleedout state that required an elbow to the neck to down an enemy and ridiculously OP SMGs that... excelled at close range. Literally everything forced the player into CQC if they wanted to achieve any amount of success in PvP.
Make long range viable instead of gimping close quarters for no reason.
The release is 9 months away, I hope you can get all of this right and make The Division 2 an even greater game than its predecessor.