Whenever the model for the vehicles gets revisted, I would like to suggest the following

1.) indicator for the turrent relative to the hull. This could be very simple or complex, depending on how it's done. It could be as simple as putting a clock number under the ammo counters. 12 for lined up forward, and so on around through the entire turrent travel. This could also be a small animation with a rectangle (hull) and a circle and line (turrent) that gives relative position, placed much like the clock number. To get complex, most German tanks had a revolving ring in the commander's cupola that turned opposite the turrent and gave it's postion relative to the hull.
What I'd like to see is two gauges in the main gun sight, one that gives elevation in degrees, and the other gives turrent position in degrees. 0 or 360 is pointing foward in relation to the hull. This however should only be in the gunner's position, and not the commander's.
2) Most functions of the tank should be controlable from the commander's cupola. While this is not historical in a mechanical sense, it is true in practice because the commander can give orders to the loader, gunner, and driver and thus control the tank entirely from the cupola providing everyman does his job and obeys orders.
For example, the commander should be able to tranverse the turrent. He can rotate till on target, but due to lack of precision (except at very close range) the gunner would have to take over. This is very easy, for a player would merely need to switch to gunner mode. Now the commander may not be able to hit anything (without a way to precision aim) with the main gun up there, but the position should be capable of firing it (such as spotting when firing HE shells, in our case, shooting at hangers at close range) as well as the coaxel gun.
Same goes for driving: steering, speed, and gear selection, as well as stopping of course.
By making these functions available at the cupola, it simulates how the commander is the "life" of the tank, giving orders that determines how a tank functions in combat.
(I'd just like to be able to creep, stop, line up, and then shoot, and creep again in short order )
3) Buttoned and unbuttoned cupola. Now whenever the commander is exposed firing the burp gun he is invunerable, I'd like to see a buttoned mode with periscopes (well, I'd like to see periscopes for the driver/hull gunner position as well) When he's unbuttoned he has a high chance of dying when being shot at. From then on the multi-function cupola (from above) would no longer be available, and tanking would have to be done like we do now.
4) moveable burp gun in the hull gunner's position, with some type of aiming device

5) At least some smoke from main gun discharge
6) track marks of some kinda, and dust at high speeds
To deal with the commander's cupola with multi-function, I think perhaps Panzer Commander had the best approach with a few adaptations for AH.
Rudder input can steer the tank, throttle controls, well throttle for though the gears.
Brakes need to be like air craft brakes, a button press I think would work better then using the pitch axis (plus it resloves working the throttle from the cupola)
The trim keys, such as J and L to control powered traversal of the turrent, and I and K for elevation (elevation is normally very slow anyway). Regardless of zoom, using the J and L the turrent would traverse at the same speed (max), and a seperate key set for fine adjustment (which was hand cranked on quite a few) such as M and ,
Since we all use these in flight normally I would like to think it wouldn't be too much of a problem getting use to. This would still leave the X and Y axis to control the AAMG., and the views open.
7) Not a major deal but maybe a turrent centering device to tide us until proper positional gauges

8)... NO EXTERNAL VIEW!

9) Because of #8 how about a set of binoculars for for unbuttoned cupola?

- Jig