Its about DPS taken, not the number of models. As i said to luciano, if the squad members had 2 men each with 1 hp and 100% received accuracy no one would be complaining that they are too durable.
No, its about
effective damage taken. This game has directional damage applied to specific models based on a statistical distribution, mitigated by terrain and distance factors.
Two models allow you to defer, delay or spread applied damage from the distribution by leveraging the distance and specific models portion of the equations. Thus more models creates a moderately higher effective hp. This means the number of models a squad contains is a VERY BIG balancing factor when considering durability. See the age old arguments of 3 ostherr man team weapons vs 6 man soviet team weapons from the good old days, or 4 man grendiers vs 6 man grenadiers.
In the case of a retreating sniper squad you're usually only ever shooting on model at a time, the second model is taking no damage or partial damage. This results in cases where both models have 2 health, took no model losses and are safe in the base.
In the case of a mortar shell that 82 damage isn't being fully applied to the entire squad. Unless you've magically put both snipres models at the center of the motar shell, they will either both get out with low health or only lose one model.
In the case of a tank shell hitting a sniper, you're applying a ton of DPS to one model but not the other. So even though your tank shell dealt 100-120 damage, you only applied it to a single entity with 45 health or so. Wasting over half of the damage.
The two men arent the source of that issue though, seriously, nerf its received accuracy so that it is extremely flimsy to rifle and mg fire and now it is no longer too durable.
They are though. For the exact same reason a conscript squad has more chances to retreat then a grendier squad does. This game is about directional damge applied to specific models.
The situations you make i dont think apply:
Big flanks clip one model, the other rounds the corner: quite a niche situation (also why shouldnt good positional play be rewarded inherantly), but nerf its received accuracy and you increase the rate at which both models die or a retreat is forced / make this play harder to pull off for the soviets, tweaking for balance but RA changes could sort this problem.
You really can't increase RA more then it is. Snipers already take damage really easily; increasing it anymore will create situations where literally every shot will land on them. Snipers will start dying to right clicks, not flanks - making them not worthwhile building. The RA on snipers is already high, and the patch attempts to bring their retreat RA closer to their base one to help reduce the frustrating retreats thing.
Mortar shell: 1 man snipers dont die to a mortar shell already, with 82 health and 1 model the soviet sniper wont either. The soviet sniper is the only team that CAN curreently be 1 shot by a mortar at the moment BECAUSE of its 2 man squad, this backs up my statements not yours?
No the sniper team won't die because you have two models, that are a distance apart. The shell lands in one spot, not both. Unless you're bunch your sniper together in which case, rip.
Werfs are more likley to kill a sniper model (or squad) because of the saturated scatter Aoe profile it brings as opposed to single point and radius.
222: increase its RA so after a fair (edit: i mean "balanced" fair has ambiguous meaning here i realised) amount of time under the 222's guns the sniper team dies. This is again not intrinsically linked to two models, but to not taking enough damage from small arms.
222 increased accuracy is already in the patch notes, its a problem against all infantry not just snipers.
Cloaked falls: again increase its RA so they basically gib the squad under these circumstances.
RA doesn't help that much this situation (unless its really high, but we went over why you don't want it higher then it is), since damage is applied in a directional manner against specific models. Your falls target one model and volley him. The retreating model already home free. Or they split their fire, then one model gets sslighlty out of range and they switch fire from one model to another - failing to kill the first model they targeted.