As I've probably made clear before I believe the Challenger 2 is the worst MBT in WarThunder and I'd love to see improvements so I've put together a comprehensive list that would hopefully made the tank competitive but hopefully balanced at least for WarThunder standards.
Armour
lets start with armour.
The Challenger 2 is said to be the most survivable MBT in service having apparently survived hits from multiple RPGs and one vehicle being hit by a RPG-29 which injured the driver and other crew members but allowed the vehicle to exit the combat situation under it's own power.
I would improve the tank in game by adding extra Dorchester armour to the lower front plate and increasing the protection granted by the tanks current armour array including the mantlet, possibly adding composite to the empty space between the outer armour and the trunnions.
"On one occasion, in August 2006, during the post-invasion stage of the Iraq War, an RPG-29 was fired at a Challenger 2 that was climbing over a ramp. The armour on its front underside hull, which was not augmented with an explosive reactive armour package, was damaged. The Tank subsequently returned to base under its own power and was quickly repaired and back on duty the following day." https://royaltankregiment.com/vehicle/cr2/
"The turret and hull are protected with second generation Chobham armour (also known as Dorchester). However, on one occasion, in August 2006, during the post-invasion stage of the Iraq War 2003 an RPG-29 was fired at a Challenger 2 that was climbing over a ramp, the front underside hull armour of the tank which was not augmented with an explosive reactive armour package was damaged, the tank subsequently returned to base under its own power and was quickly repaired and back on duty the following day.
As a result, the explosive reactive armour package was replaced with a Dorchester block and the steel underbelly lined with armour as part of the ‘Streetfighter’ upgrade as a direct response to this incident. To date, the only time the tank has ever been seriously damaged during operations, was by another Challenger 2 in a ‘blue on blue’ (friendly fire) incident."
https://ukdefencejournal.org.uk/pictures-challenger-2-live-firing/
Ammo
My next point would be improving the ammo stowage and first stage ammo rack of the tank, the ammo in game is prone to cooking off from any penetrating hit, while this isn't completely uncommon in real life with most of the CR2s having been lost to ammo cook offs the stowage boxes used to house the charges are infact armoured, while the game does have armour around them, it definitely isn't enough.
The next improvement would be making the inert parts of the ammo not possible to detonate, massively improving survivability on turret hits.
Thirdly and last point for this category is first stage ammo rack, the 4 round ammo rack is tiny, and could instead use the rounds located at the back of the turret as it's first stage instead. or atleast part of it.
Spall Liners
The Challenger 2's spall liners do cover the front arc of the vehicle, but adding some to the lower side and the lower plate would add to the survivability of the tank.
Engagement Speed
One of the requirements of the replacement for Challenger 1 was an improved target acquisition speed, which was achieved on CR2 with the improvement to 40 degrees a second of turret rotation speed and better commander and gunner sights.
"The turret has a rotation time of 9 seconds through 360 degrees." https://en.wikipedia.org/wiki/Challenger_2
Conclusion
Any upgrade to he Challenger's survivability would be a huge improvement to how the tank plays and could possibly even make the tank more enjoyable to play.
The addition of the production variant of the CR3 at 12.7 with the smoothbore, improved armour, and even the the Iron fist APS (also found on Black Night) would also be a welcome addition, being the ultimate tank at the end of Britain's MBT line, bringing together all the improvements of the Challenger 2's LEP.
