First let me say Kudo's to Superfly on this one. This is definitly IL-2 quality graphics work on this one. Beautiful really!!
Anyway enough butt kissing.
I know virtually nothing about the Ju-87 so I pulled up a quick web search and this is what I found.
Ju 87D (D-1/D-2/D-3/D-4/D-5/D-7/D-8) - The Ju 87D had a completely redesigned engine installation. The engine was still a derivative of the Jumo 211, but the more powerful 1,410 hp (1051 kW) 211J-1 or 1,500 hp (1119 kW) Jumo 211P model was used depending on the version. The main coolant radiator was removed from under the engine cowling, and two radiators were installed under the wing centre section instead. A shallow oil cooler was retained under the engine cowling. A new constant speed Junkers VS-11 propeller with paddle blades was used. Increased armour protection for the crew was also introduced. There were also other aerodynamic refinements. The greenhouse canopy now tapered aft, instead of having a nearly constant cross-section as had that of the B-model. The aft gunners exchanged the single 75 round drum-fed MG 15 machine-gun for twin belt-fed MG 81 machine-guns.
The bomb release gear was better faired in, and the maximal bomb load was increased to 3,969 lbs (1800 kg). This could include a single PC 1400 3,086 lbs (1400 kg) armour-piercing bomb on the centreline rack. The landing gear was again strengthened, but nevertheless the Ju 87D retained a reputation for landing gear collapses on rough runways. The wheel covers were again changed, and the fitting for sirens were eliminated, but after 1942 the spats and wheel fairings were increasingly discarded. The Ju 87D-2 was basically a D-1 but strengthened to equip a glider tow hook.
The Ju 87D-3 introduced even more additional armour for the crew and vital parts of the aircraft reflecting the Ju 87s increasing use as a Schlachtflugzeug (close-support aircraft). From the D-4 model onwards the 7.92 mm window guns were replaced by the 20 mm MG 151/20 cannon. The Ju 87D-4 was a torpedo-bomber version capable of carrying a single torpedo with only a few example built. The Ju 87D-5 model had a longer wing span, with pointed wing tip extensions for use as a dedicated close-support version with jettisonable landing gear and no dive brakes. An interesting development was the Ju 87D-7, a night ground-attack model converted from Ju 87D-3s and Ju 87D-5s with a 1,500 hp (1119 kW) Jumo 211P engine with exhaust pipes extending back across the wing. The Ju 87D-8 was a day version of Ju 87D-7 without night-flying equipment and flame-dampers. The wing mounted machine-guns replaced by 20 mm MG 151/20 cannon and dive brakes were omitted. The Ju 87D-8 was the last aircraft type in production when in September 1944, all aircraft production other than fighters, was terminated.
So in other words if we had the D-4 instead of the D-3 we would have a 20mill defensive cannon instead of a 7.92mil. Why not just give us the D-4 so it could fly in the MA a little better?
Also the twin 37mill anti-tank option didn't show up until the G series so that armament is also out of the question.
Why?