Deep Dive - Sight lines, Visual density and similarity.

the Initial question:

In modern level design, it is extremely easy to go overboard in the way of environment art, games like Battlefield 4 and mad max constantly have problems with players getting lost and confusing sight lines due to busy texturing, and crowded prop placement. The main question I have is how that concept of crowded prop placement and busy textures can be scaled with the difficulty of a game, in short, at what point does environment art become a hindrance and can that effect be scaled to effect the challenge level of a game?

The Experiment:

In unity a simple FPS system has been created, players have access to one rifle, grenades and simple movement/aiming mechanics, they will be placed into 3 levels, each are iterations of the same level, however each have larger amounts of props or change in lighting.

Each player will be asked to play through each level, at the conclusion of each level, the player will be asked to fill out a small form which will be funnelled into a spreadsheet for documentation, this data will be used to make correlations and answer the initial question.