As it stands, based on currently implemented mechanics, a vehicle with a more detailed model will be more survivable than a similar vehicle with a less detailed model.
One reason is volumetric. If you have more modules that extend to their full proportions, you get better protection.
Another reason is the presence of certain modules. A glaring example that is debated right now is the T-90M’s spall liner, or previously the Relikt of the T-80BVM.
There are many vehicles in game that have spall liners IRL but do not have them in game. There are also some vehicles with anti-KE ERA armor, but so far only the Relikt is modeled with anti-KE properties.
There are several reasons why Russian vehicles, for example, are more detailed. One is the pool of model makers that work on Russian vehicles compared to minor nations. There are also naturally more models created for larger nations like the US and Germany, than, say, Japan, Italy, or Sweden.
Another reason is that some nations are more revealing and some are less, about their armored vehicles. Whether in technical details, or even the internal arrangement.
Russia is particularly revealing about its vehicles. For example in 2015 when the Armata was unveiled, more details about it were given that day than what was gathered over decades about armored vehicles in service around the world.
It is therefore enticing for Gaijin to add something like the T-90M with its full model as it has access to all the data, but much less enticing to do guess-work for other tanks when the data is scarcely available.
I propose that in the presence of data for one vehicle and absence of same data for another, said mechanic/detail be avoided until data is available at least for some majority of vehicles, say 70% of the same type.
Got data on the T-90M’s spall liner but not on any other MBT? Great. Set a flag for it and turn it on when you have finished modeling spall liners on at least most other tanks that have them IRL.
Spall liners are of course just an example. There are other examples out there, gathered over the years, of preferential treatment given to certain nations regarding the implementation of mechanics and capabilities.