Maxperson
Morkus from Orkus
The bigger problem is that the experience of "realistic-ness" is entirely subjective, and neither you nor Max can possibly be qualified to dictate the terms or context of someone else's subjective experience.
It doesn't matter what they experience. They can experience it as a moon made of cheese and that won't change the fact that there was some amount of realism increase. The value each person places on the realism increase based their perception of it can very wildly. That there was a realism increase is set in stone.
The even bigger problem is bound up in the initial premise of this thread. Reality is characterized by an infinite number of variables from which complex phenomena emerge.
This is no problem at all. Realism =/= reality, so it doesn't have to take all of those, or even most of those into consideration. The fewer variables you account for, the smaller the realism increase.