Too many suggestions and some feedback for the two MBTs currently implemented as of Squad v12.2: T-72B3 1) The time between reloading rounds from a loaded chamber in game is identical to that of reloading the gun from an empty chamber. This should not be the case. Contrary to popular belief, it is indeed possible to unload shells from a T-72, though the process of doing this should add considerable time to the entire reloading process. (This assumes one does it the proper way in game, not using an exploit to mitigate any time between changing shells.)
Here is the real life process: the commander must cycle the auto loader to an empty munition cassette and manually eject the propellant from from the chamber via the breach operating handle. The T-72's ammunition comes in two separate parts, propellant and shell, and so the shell is still in the chamber; this must be removed from the open breach by hand and placed back into the cassette.
(Just a note. While it is possible to switch between rounds, I do not believe this is a common practice. Such a system is in place for clearing malfunctioning rounds from breach; it would be much more simple to fire the loaded round down range and then load normally.) 2) The arming distance of the 9M119M guided missile appears to be around 150-200m in game (as measured with the in game LRF). The effective range of the missile should start at 100m. 3) The PKT co-axial machine gun is fed via 250 round belts via 8 boxes in total, not a continuous 2000 round belt. 4) The way the commander utilises the NSVT heavy machine gun is incorrectly modelled, and it appears that the commander's cupola resembles no T-72 design. The commander must turn out to use the machine gun. (Perhaps a placeholder, balance, something else?) The NSVT should be fed from 60 round belts, of which there are 5 boxes in total. 5) Traversing from a standstill by setting the vehicle in first gear (just hold 'W' until you're in first and then release), and putting all power to either track (to traverse left or right) causes the transmission to rapidly switch between the first and neutral gear.
(Which can be sort of solved just by holding 'SHIFT' to hold the current gear, but the jittering of gears sometimes accidentally makes me hold the neutral gear.) M1A2 1) Same problem as number one from the above section, with less explanation. Should be longer, as extracting a shell from breach, stowing it into the rack, and placing a new one in takes much more time than reloading from an empty chamber. 2) The GPS (gunner's primary sight), a periscopic sight mounted above the turret, known as the 'dog house' is the preferred sight to use rather than the GAS (gunner's auxiliary sight), a telescopic sight, and which is the only sight used and implemented.
(The GAS has a fixed zoom of x8, while the GPS has multiple zoom levels of x3 and x15. There are other zoom levels, though those can only be used with thermals ON, which has yet to be implemented.)
3) Neutral steering is a bit finicky, and is actually done from the first gear. ______________
Thanks for reading through the entire span of this overtly verbose and lengthy post.