Once again, you don't address the question which related to the 30-degree from perpendicular average measure used to calculate shot penetration. I was addressing how some designs or shot angles may be modified to address some design geometries which may alter the calculation. We weren't addressing vulnerability analyses or tactics, but armor penetration calculations
I actually had/kept that in mind, I just wanted to warn that during the collection/research of penetration tables one may confuse the different standard angles, no more, no less. There is one or another wargame where the developers created invulnerable German tanks, unintentionally, because they misinterpreted the German standard angle.
I didn't address your suggestion (45°), as I didn't have much time.
I do think that it would create an unjustified advantage for tiger tanks.
It was standard procedure in German units to angle their tanks, if their tanks' front sections featured vertical plates/turret faces and if they encountered enemy tanks with somewhat more potent guns. So, yes, there's that.
But terrain layouts, visibility conditions, etc. were vital factors, too.
Sitting in a confined boxy field surrounded by hedgerows, without the possibility to engage at range, didn't really give a Tiger much of an opportunity to angle, when it was swarmed by enemy tanks, for instance.
The T-34 (43) actually had a chance to penetrate a Tiger's frontal plate at the lower end of medium ranges.
The Germans evaluated - when they created the Tigerfibel (the manual with comic-style explanations) - that at around 500 meters (between 84 and 96 degrees) the T-34's gun could pierce through the frontal armor, at least. Shots at the side armor and the rear armor were a different matter, tho, the T-34 could score hits from 1500 meters out on the Tiger's side (EDIT: angle of impact: ~ 88° to 92°), and - even at seemingly unfavorable angles, particularly ranging from around 58 to 120 degrees - at 600 to 800 meters.
The Germans called these zones (the enemy should not be allowed to enter) "shamrock" leafs, and even illustrated those zones in the Tiger's manual, explicitly.
Below, you'll find the shamrock leaf (pretty basic visualization of the actual calculation) for the T-34(43), green = vulnerable to succesful T-34 shots, red = the max distance to kill a T-34s, where dark red marks the max distance for a successful hit on the T-34's glacis plate - 800 meters -, the light red part refers to side and rear penetrations on a T-34.
In practice, the 88-mm gun (in 88-mm flak gun emplacements) scored confirmed kills at ~2400 meters in North Africa, Tigers scored hits above 2000 meters in the Russian steppe, so the 2000-meters mark doesn't mark the max. effective range, it's a mark where a Tiger crew could still expect a shot on the side/rear to be a kill shot.
A quite common Russian tactic (or attempt) was to try to overwhelm single Tigers by rushing their positions in larger groups. The goal was to get within the 500 meters "leaf" and hope for being able to place a clean shot at perpendicular or almost perpend. angle.
With enemy tanks being held at bay with long distance shots, a Tiger could easily angle and pick off enemy tanks, but even rushing groups could be decimated rather easily (sometimes up to 20 or 30).
But when survivors closed in, some Tigers were actually penetrated (frontal plate) during such engagements, or their mantlets cracked (I posted examples/fotos in this forum a while ago, showing the turret replacement procedure in the field, using a mobile crane installation), but the tanks often remained operational, so they popped smoke and managed to retreat - despite the mess inside (eg. shredded or injured crew member) and were temp. fixed in field repair shops quickly, until the unit commander could afford to send it to a factory repair hub or to the factory in Germany for more thorough repairs.
Some footage covering Tigers on the EF actually shows that Tiger units didn't even bother to angle at times, as their max effective ranges and their optics were so superior.
It seems like more units angled again, when more upgraded T-34s appeared. During the Kursk operation the Tigers were ordered to act as breakthrough tanks, facing numerous AT gun belts, the orders and some footage suggest that quite some of them couldn't angle during pushes, as the shells kept coming in from a whole range of different angles, including straight from the front, anyways, while they focused on pushing and on clearing the AT gun positions in front of them (some targets were actually as far 2800/3000 meters away [they had to aim up, for arched trajectories and observe/adjust the fire], the author of the Tiger manual explicitly covered the Kursk experience and encouraged tankers to fire at long-range targets, eg. AT gun positions) or say at 10 to 2 o'clock. The other tank types were ordered to secure the flanks and engage counterattacking/flanking enemy tanks and/or infantry closing in.
During a few engagements in France, especially in hedgerow country, rushing Shermans actually managed to knock out some Tigers (eg. hit in the rear, knocking out the engine to immobilize a Tiger) by swarming them and trying to get to their sides/rears, as the standard Shermans had to get as close as 200 meters to score a penetration on the front.
So, if you change the angle to 45 degrees for the frontal armor, you deprive the Russian tanks in the game of the chance to score straight frontal hits above 200 meters. In practice and historically, it was tricky/stressful/hard to angle on a group of tanks rushing your position in line formation and kill all of them before survivors made it to the sire/rear, for instance, despite the fact that a well trained and experienced Tiger crew could manage to fire every ~7 to 7.5 seconds. Accordingly, if you'd also introduce the angle to the side section, you'd completely take away the fact that the vertical 80-mm side armor could be penetrated at medium range (and maybe even easily, depending on ammo type/gun specs).
You point out that tactics weren't part of the discussion, but historically enemy tanks got in medium and close range and scored successful hits on Tigers, on the front, on the sides or on the rear. That a penetration didn't necessarily knock out/immobilize (and maybe "just" kill or injure a crew member) a Tiger would be another story.
You also see enemy tank units closing in, in the game, which is realistic IF the manoeuvre is carried out at top speed and if the attacking group loses quite a few tanks in the process.
A calculation routine behind the actual shot calculation can actually simulate the historical hit rates, by assuming that a certain percentage of hits on Tigers will be successful penetrations, for instance, and/or by considerung the actual facing of the tank (unit).
I could imagine that such routine or a similar routine is in place. If not, it should be in there, imho.
If you put in 45 degrees on the front, you make the Tiger less vulnerable then it actually was, and that would be a pretty ahistorical setting.