Okay, my 2 pfennig's worth on the APCR/AP/HEAT/etc loadout issue:
The PzIII has a dedicated APCR loadout to balance the vehicle's game peeformance; it may or may not be historically 'correct' but it goes a long way in the playability category.
Now, it's been noted that other tanks carried a variety of rounds- an dI certainly don't disagree. HOWEVER, for playability, let's assume the developers (and this is pure conjecture) had in mind to use the two primary rounds employed by tanks- these being AP and HE- in an effort to 'unclutter' the already hectic turret management problem (that being the phenomenon of a 1-man turret all around).
Let's assume, for argument's sake, that a tank gunner knows his stuff and will call for whatever he thinks is necessary at the time. So a RL gunner has AP/APDS/APCR/etc at his disposal- could ALL of these not be encompassed by the overall 'AP' category? The same applies for HE rounds; the gunner has HE/HEAT/HESH/etc to choose from.
So you don't get to choose *exactly* what round you personally want in a given situation? Maybe you DID get that APDSFS round and it was ineffective; maybe that HESH round you blasted Ivan with didn't do squat. What does a competent gunner do? Try something else, or fire from a different angle, or any number fo remedies.
My point is, just as a number of compromises have been made in the tank modelling, so too have they been made in the gunnery aspects of RO. We still don't have a 2-man turret, we don't have signal flags insted of radios for early war Soviet tanks, etc., etc., etc. So we are given a choice of AP or HE in battle- let's live with those two choices and (at the risk of sounding like a Real World Idiot) fight with the tank we HAVE, not the one we WISH we had. If a future update or mod comes out that accurately models the myriad number of tank ammunition choices, great- until then, I'm happy with the AP/HE mix.