Gentlemen:
The problem with the IL-2 can be approached following two patterns:
(1) Problems with the design itself. A slow, clumsy flying armored pig, uncapable of surpassing the top speed of the Stuka which had, for instance, a non-retractable undercarriage.
Also manouvering was horrible in the soviet design. One can understand the kind of nightmare dozens of thousands of USAAF airmen endured -and the countless psychiatric cases such missions produced- when they had to fly in those real large metallic tubes with wings, carrying several tons of bombs inside, knowing that you were slow and that manouvering was simply impossible: "what you will do is simple: fly straight ahead and learn to handle those .50 cals".
But when one knows manouvering was about impossible for a single-engined plane, which unlike the Stuka could retract its undercarriage, then perhaps you might consider re-thinking your views on the IL-2.
To make the long story short, the IL-2s never did come nowhere near in destroying the number of panzers claimed by the soviet department of mythology. The tale, however, does not end there. These soviet guys also portray the IL-2 as an "extremely efficient" destroyer of German fighters as well. (!)
In fact, and as Mr. Primus pointed out, the IL-2 got fitted with a rear-gunner, which of course provided the model with a minimum level of self-defense abilities.
That particular characteristic has been totally, overwhelmingly overhyped and overinflated. You can read things -hogwash- like "the rear gunner in the IL-2 came in as a nasty surprise for German fighters". I´d respond to that piece of jewelry "no shit!".
That some German fighters were indeed shot down by IL-2 defensive fire? Sure! So were RAF fighter pilots by Stuka rear gunners. The issue will of course follow a pretty similar fashion as in the case of panzers allegedly destroyed by IL-2s in huge numbers: they never excelled in that department.
The problem will rise to the surface quite pretty soon here though: if the massive boxes of four engined heavy bombers, each machine fitted with up to 10 .50 cal machine guns were doomed against the swarms of Bf 109s and Fw 190s, one can only wonder what made those mythologists believe the IL-2 could tangle with German fighters homing in for the kill.
The answer is simple: with or without a rear-gunner, the IL-2s are losers against fighters.
Yes, it was heavily armored, but there were other -more important- problems for German fighter pilots intercepting formations of IL-2s. Sometimes the IL-2s flew at very low altitude. Intercepting at such low altitude is always a dangerous task, but the danger of flying so low also affects the intercepted part and not just the intercepting side.
I have guncamera footage when you can clearly see many German pilots had a thing for aiming directly at the cockpit. At certain distance, the MG 131 on top of the cowling of 109s and 190s, and of course their cannons, did not have trouble to kill the pilot, sending the IL-2 to bite the ground.
Some films are even disturbing: images of rear-gunners turned into human torches jumping from their positions.
(2) Problem number two gentlemen: the kind of crews which flew the IL-2. This is the ultimate issue.
Hastily trained crews virtually uncapable of achieving anything significant, unless they got launched to the battle in massive numbers, as it was in fact done during 1944.
The very well trained crews of both the RAF and USAAF had a very rough time in hitting any German panzers. The question: what made these soviet propaganda boys believe their ground-attack crews were that good, or even better than those of their western allies?
I have met veterans who survived flying the IL-2 in the furnace of 1944. Horrible mutilations and stories. Accidents when landing were the rule. Crashings when approaching the battle zone at very low altitude were very common as well. One of them told me that he saw this crashings in absolutely all the missions he flew -by the way, a not very high number of missions: no more than 15, until his plane got blown out of the air by a Bf 109.
The nearly 1 ton of armor in the model was in fact very helpful against light weapons, when they were greeted by enemy troops from the ground. Not against Flak, much less against German fighters.
They told me that the greatest successes of the swarms of IL-2s were against large concentration of enemy troops, supplies and vehicle lines. Those were the occassions when they indeed inflicted horrible damage to the Germans.
Whenever they saw German panzers manouvering on the battlefield and the IL-2s appeared, hitting anything could be some sort of a dream. I asked abouth the so-called "circle of death" portrayed as some sort of "brilliant" tactic to approach German panzers from the rear, where their armor was thinner. Hogwash.
Many guys even resorted to smash their planes against German motorized columns!
The IL-2 will certainly have the Gold Medal for the most shot down plane of the war.
It is most unlikely the soviets could produce the number of IL-2s they did without the vital aid of Lend Lease.
As conclusion dear gentlemen, the combination of these 2 problems: a mediocre design and hastily trained crews makes the IL-2 an unlikely candidate to get the award of the best tank-destroyer.
It made a contribution to the soviet war effort; it was not a good tank-destroyer though.