... as the 2cm guns do the same thing in a slightly different way: kill infantry. ...
Their mechanism are completely different.
The different behavior add complexity for not good reason.
Actually the 222 cannon does very little damage to infantry most of the damage comes from mg.
...You're gonna have to accept that the majority of the game as it currently functions is here to stay at this point and there can only be small balance changes rather than complete overhauls....
These changes are simple and do improve the game. They are not overhauls, but even that theory hold little water since the game has see much more overhaul since Relic allowed other to work on the patch than before.