I feel like the only reason you're saying that it has too much detail in places the player won't see is because he's showing screenshots of the detail he's done in places the player won't see. He's showcased the areas. While in game, you're right - A player will not notice all the wonderful buildings on the cliff. However, it's like that in all maps. You have a bunch of detail in places you don't normally look at when fighting the other team. If you had detail in the yards and on the points, you wouldn't ever take them in because you're fighting in the yards and on the points.
How many times have you gone through a Valve map and been like "Oh shit, I never saw this before. That's cool" or some other similar exclamation when you're not shooting a scout in the face with a crocket or otherwise playing the game? You notice the detail when idling around waiting for a fight. And detail on the cliffs will do just that.
If anything, there needs to be a tad bit more detail on control points for the sake of letting them be beacons so everybody knows their target.