In online games, there are generally two necessary aspects to "getting good": game knowledge and understanding your opponent. Game knowledge includes game mechanics, which are obviously necessary, but also includes esoteric knowledge like the specific areas in a map that can be exploited just so, or a complex combo with specific spacing in a fight game, etc. Personally, I don't want to spend my limited game time memorizing complex game knowledge. To me, the fun comes from understanding the opponent and using that understanding to beat them: what are their habits, how do they react, how can I trick them, etc. Levels like fy_iceworld are perfect in this regard.
> there are generally two necessary aspects to "getting good": game knowledge and understanding your opponent
At the risk of overcomplicating an astute observation, I'd say that there are actually three aspects: game knowledge, maneuvering, and metagaming. That is to say that the ability to understand your opponent is fundamentally separate from one's ability to effectively foil them.
Iceworld embodies the platonic ideal of a maneuvering test by massively compressesing the total number of possible gamestates into a 3x3 grid of sightlines. The map itself isn't exactly a masterstroke, but it's nonetheless extremely impressive in the way that it manages to avoid collapsing into degenerate gamestates after jettisoning so much complexity.
I generally agree, but the thing with these small maps is that you don't have time to "understand the opponent". Kill times are in the order of seconds, and death comes from every direction. There's no place to hide, strategize, and out think your opponent. In many cases, you can get away with aiming at the enemy's spawn point and rack up a dozen kills in a minute.
At least some CoD maps like Shipment, Shoot House and Rust have a bit more complexity, places to maneuver, and, yes, even camp for a short while. The biggest thrill is always rushing to the top of the tower on Rust, where you feel you have a clear advantage, and conversely, taking revenge on that pesky tower camper.
I haven't played fy_iceworld, but think that boiling that formula down to where there's absolutely no place to hide, removes any strategy at all, and staying alive becomes a matter of luck, rather than skill.
CS struck a great balance between skill floor and skill ceiling, which is one of the reasons I think it was the first blockbuster multiplayer FPS: even if your opponent is a way better player and knows the map, it's still possible to get lucky and win. The same isn't true of games with a higher skill floor like Quake duels*
*RA3, a Quake mod which came out around the same time as CS, lowered the skill floor by giving players a full loadout of weapons and maximum health on spawn. It was good!
