They only carried 37 rounds so you would have to be spot on to kill a tank in one.
It doesn't matter if they carry only one round each. The guns, if modelled according to spec, will penetrate the armour and cause a disablement/kill against any tank in the game.
Vets make it sound as if killing tanks with IL2s or Hurri2Ds is an easy task, but in reality both planes need a fair amount of practice and stable skill level to achieve real success as an anti-tank platform. The IL2 often requires a solid barrage of 23mms to pop a tank, and the frail Hurri2D 40mm (which is actually weaker in penetration capabilities than the IL2 23mm) needs a precise aim at a precise spot to do the same. And this task must be carried out often at deep angles with fast closure rate at low altitude.
Out of about perhaps 4x IL2s that might buzz around a single enemy tank closing in to the town, 2~3 of them are usually average people who go crashing into a tank without being able to disable or kill it. It takes them 2~3 deaths to poke a tank in the right spot to kill it. Specialized anti-tank planes are a large threat to any ground vehicle, but the ultimate equalizer in favor of tanks is that it actually takes good skill to kill a tank. That's the reason the current ground war is more or less balanced for good gameplay.
The Ju87G 37mm anti-tank cannon changes all that. It puts AH right back to the days of old AH1. Even 50cals would pop a Panzer tank in those days, and when GVs approached the field people upped Spitfires to kill them. As a result, the Panzer4 was all but extinct in the field, and the ground war totally consisted of only Ostwinds. The Panzer4 was a hangarqueen.
Therefore, the need for the perk is evident. If the Ju87G is unperked, a single, terrible pilot in a Ju87G would be able to stop a whole convoy of tanks attacking a town. Approach a tank, land 1 shot on the tank and kill it, crash/auger death, reup, rinse and repeat. At least with the IL2s or Hurri2s, a sucky pilot has a low chance of disabling so many tanks in a given time.
Personally I don't think anyone who's gunnery is not that good would be very good at killing a tank with one.
In a real world where people fear the kingdom come, you'd be right. However, in AH people reup. They don't need to be good with gunnery to kill a tank. All they have to do is up a Ju87G, fly to a tank until the tank fills the front windscreen, and then go kamikaze into it with guns blazing and the tank would pop. That's how powerful the 37mm is.
People already do that with the Il2 and Hurri2D - the difference is, these guns aren't as powerful as the 37mms, and one is rarely successful in actually killing a tank.
Not to mention that the Ju-87 is a very slow plane and being low to the deck for tank killing, vulnerable to say the least.
The very fact that the Ju87G will only be used within 5 mile radius of one's own home base, with friendly fighter planes swarming around, is already enough to negate that problem. How often do you see IL2s or Hurri2Ds flying to the enemy field 25miles away, to take out defending enemy tankers?
Maybe someone like Ack Ack or a few others I know of could be good in one off the bat but others will have to have some practice to actually be good in one.
You don't need practice with a gun that kills any tank with a single shot at all angles, all distances. All you need is the balls to fly into a tank with guns blazing - wether or not the attempt kills you.
And as it is, the n00bs of AH have six balls and no brain. You don't wanna encourage them.
