Light tanks are highly mobile and can wreck ostheer on maps like kharkov, minsk and other large maps and thus solely relying on Tellers or paks or PGrens is not desirable.
Therefore Ostheer need a light tank of their own or any vehicle capable of countering the other factions' light tanks.
UKF didn't have trouble against light tanks, and now they don't even need one since the PIAT is definitely the best HAT in game in the preview mod.
I disagree. WM does not need a light tank, and they already have the ability to counter M20s, M15s, Stuarts, AECs, M3A1s, and T-70s.
A concentrated force of some Grenadiers, a Pak, a mortar, and a 251 Halftrack for reinforcement and extra DPS is brutally hard to counter. All you have to do is push on your enemy's cutoff with force, and you will force your opponent to commit light vehicles or risk losing the tech battle, as you can get out a P4 or an Ostwind soon after your enemy has fielded a light vehicle of their own. Just watch Gentlefox play WM.
If you want to use 222s to counter light vehicles, make 2 of them and use them as a reactionary force--wherever the enemy light vehicle attacks, you send in the 222s. Don't yolo-charge them in and keep them alive. The sheer HP pool and their DPM, combined with your infantry/team weapon support force your opponent to back off.
The Brits actually have issues with multiple light vehicles, such as 222 spam. One AEC can be taken out by a pair of 222s, while three 222s is a certain kill as long as you don't hit a mine or yolo into a 6-prd. Therefore, Brits actually have to play quite conservatively with their AEC 2 min after it hits the field, lest a 222 wolfpack take it out. For OKW, the Puma is a pretty good unit in keeping an AEC away.
The main idea is, if you negate the impact of of your enemy's light vehicle, then you have effectively stopped them from using it to gain a map control and tech advantage. Currently, the WM can do that, and the Winter Balance Preview Mod puts the 222 in a much more reasonable position. Previously it was overpowered, due to having such a low price.