No, because of the caliber and armor penetrating qualities of the main gun, as well as the armor and firepower of the opposing vehicles (stuart/t70/aec).
Like I said, best option is to have an interim P3 forcing players to make a decision weighing fast t3 or more stable mid game.
The 2cm gun can penetrate Stuart, T-70 as well as the AEC. It could also penetrate the T-34 in the turret or sides. There was also a 222 variant with a 28mm that has penetrated an IS 2 in the front.
Also the T-70 had 15 mm side armour. For comparison, the German K98 SMK H bullet had 19 mm of penetration. That's small arms fire penetrating the uber T-70 light tank.
Zero reason not to buff the 222.