There are a few things I would like to see changed and added with the tanks DLC; for sake of simplicity I will make some generalisations.
Firstly, adding more vehicles with various roles and capabilities is important for a more varied and customisable gameplay.
Following on this point, ARMA, unlike other games does not need to be completely balanced, especially if there are various different tiers of vehicles, which 1 on 1 would not be balanced but balancing can be done by the game/mission creators.
Secondly, following on the previous point, realistic armour behaviour should be applied. A tank like the MBT 52 Kuma (MBT Revolution) or newer 99A Chinese tanks have in excess of 1000mm of KE RHA equivalent protection, in addition the 99A has APS and over 700mm of RHA protection against top-attack CE weapons. Even APFSDS rounds just about coming down the line fired from the L55 120mm have a penetration of around 900mm tops, with current APFSDS fielded by the US having around 600-800mm penetration.
An excerpt from a book describing a now old Chinese tank prototype (IRL) testing describes the turret armour holding up after 14x 105mm APFSDS (Slammer UP) and 6x 125mm APFSDS (T100 Varsuk). This tank prototype is already old and newer, current Chinese tanks, let alone any tanks/upgrades that would be fielded by CSAT Pacific in 2035 should have significantly enhanced protection.
As such, over a certain distance, the frontal turret armour of the above tanks cannot be penetrated.
This would create a very interesting and varied gameplay dynamic, where some vehicles have significant overmatch capabilities, making mission kills a much bigger part of the game. And removing the damage model and premise of "shoot it enough and it will blow up", whilst that works IRL to an extent, this would be good for a varied gameplay dynamic. KE penetrators should also have reduced damage vs lightly armoured vehicles and MRAPs, and can pass through without doing significant damage, module and crew kills should happen, but not every APFSDS hit on APCs/MRAPs should be catastrophic kills.
A guerrilla force equipped with only RPG-7s, would not physically be able to defeat a 99A or MBT 52 Kuma's armour, any further manoeuvres in the course of the battle will now have to take into consideration this mission-killed tank, whose crew is still alive and well, behind your lines, requiring dedication of resources to ensure the crew do not escape and prevent recovery attempts. These considerations will now affect the actions of both sides who have conflicting objectives regarding this valuable asset.
The new interiors will also add another element to a mission killed tank, having gun optics and CITVs being able to be taken out, crews can continue to rely on their periscopes and vision ports to operate the tank until those are also damaged/destroyed.
The third change I would like to see is the ability to change the types, quantities and proportions of ammunition that can be equipped in armoured vehicles, as well as reload drills that can be carried out dismounted to reload the ATGM launchers on the BTR and Gorgon.
As well as better visual effects of fired projectiles, such as the discarded sabots from APFSDS rounds. This would also add the need for crew to think before firing over the heads of friendly infantry.
Fourthly, inclusion of countermeasures such as laser jammers, laser warning receivers as well as various had and soft-kill Active Defence systems are almost a must, seeing the game is based in 2035.
