Giving 222 armor of puma, better AOE or accuraccy so it can either be sniper vehicle or AOE type, its up to you, increasing cost to 60 fuel and locking it behind batlle phase 2 (so you have to buy BP2 and tier 2) is a way to give ostheer good "light tank". Also increasing penetration just a litlle bit can be good.
Then give ostheer 222 (with mg only) into tier 2 without any aditional tech at cost of 15 fuel and 190 mp. It vet 1 bonus will be incendiary rounds so it can fight its scout cars counterparts if it manage to get vet 1.
What do you think ?
the biggest reason to buy a 222 is to have a vehicle against the stuart, t70, or AEC.
improving the armor(unless it's to medium tank level), machine gun accuracy, or AOE wouldn't improve the 222's effectiveness against vehicle.
Miragefla and your suggestion of improving the 222's machine gun ignore the most important reason why the wehr even buy the 222. In a game where all three allies faction and the okw have access to light tank, wehr is stuck with an eztaz light tank.
trying to buff the 222's anti-infantry capability and make it more expensive would just turn it from an extremely cost effective vehicle hunter into a mediocre generalist vehicle.
Also remember that USF have bazooka and the soviet have guards. Both of those would turn away even the luch pretty quickly. It's not a big issue with 222 currently because people buy them as defense against light vehicle and the odd target of opportunity, but if the 222 got an "improvement" and cost raise it's going to matter.
the current 222 is cost effective enough against vehicle to make it a worth while counter against allied light tank rush, while weak enough against infantry that rifleman and conscript repel them effectively.
USF: Stuart to also only splash 1-2 models max to prevent random wipes in yellow cover or coming around corners also reinforces its role as being more geared to fighting vehicles with some AI. Maybe tweak shell-shock vs other lights so it's not outright death. Fix USF superglue being ridiculous due to it having barely any cost or delay. Possibly raise the cost and research of Captain tech back to 70 for a greater difference between LT and CPT and give USF lower tech cost for back-teching if a Major tech is activated so they're not screwed out of MGs or ATGs.
the stuart isn't even that great against infantry. I would say that it's actually merely "decent". the stuart's greatest strength is its flexibility against infantry, vehicle, and tank. The puma is a better anti-vehicle unit, and the t70 is a better infantry muncher, but the Stuart is decent at both.