All models after the A-3 had the same wing until the Ta152s messed around with different wingsizes (the C-0 was a bit larger than the D-series). I say "all after A-3" because one of the early models started prototype stages with a slightly different wingsize, and it was changed, but I can't remember which version. Nothing that saw combat, to be sure.
This is as common a false claim as cowling-mounted 20mm cannons on the 109K-4.
The A-6 had the SAME wing size and wing function. The only difference was that a larger "bay" was opened up inside the wing to house the MG151/20 cannons, or the Mk108 cannons, or the specialty cannon pods. Perhaps removing a few braces and struts made it "lighter" but we're talking almost nothing.
The problem with requesting an A-6 is that is has ALL the armament of the A-8 but none of the drawbacks. You put it in-game and the A-5 instantly is never used again, and the A-8 is instantly never used again (it's the best of both). Now you either pick "slightly better handling" or "better guns" -- you want to kill the bombers with ease you have to pay for it in performance. You want to dogfight, you have to take the lesser-armed plane. There's a balance, a trade-off. With the A-6 there is neither, and there is no choice, you get all the guns and all the performance and none of the flaws. Poor choice to add to this game, IMO.
I'm against a A-6, because it's identical to the A-5 in EVERY way except armament.
I'd rather have the A-3. That had less armament options AND different performance. It would be a separate plane, but the A-6 wouldn't.
EDIT: P.S. Citing wikipedia is about as valuable as citing the History Channel, FYI.