Well…reading between the lines, it just looks as if the level design and game mechanics were not flushed out, yet; they spent time/money on pretty polygons before they knew if the game they were making would just ‘work’.
That is an almost unforgivable act.
- Design the game mechanics of your FPS.
- Build a ‘dojo’ test environment.
- Test.
Now, you are in an iteration-loop.
- Test.
- Make change to game mechanic &/or geometry.
- Repeat step (1)
Step (1), in UE4 is very simple and requires no compiling (unlike source) and leads to (2) which is micro-to-macro alterations of the geometry and mechanics (like TTK, bullet-spread etc, range, sightlines, scripts/blueprints) and then you go back to (1).
At no point in this loop is one building polygons in 3DMAX/Maya/Modo or anything that could be considered ‘art’. That, is really the very last thing you build and is (typically) authored by the environment artist(s).
Now, I could build you a Dojo in less than an hour, and this becomes the ‘standard’ for all assets to use.
This is also known as ‘whiteboxing’ - and if it fails at this point, the game is flawed.