Throughout its history one aspect of Counter-Strike that has been discussed almost constantly(at least in the Global Offensive era) is the balance of the maps. Certain maps have been tweaked, adjusted, removed completely even(in the case of Nuke currently and Train formerly) in the pursuit of making maps more even and conducive to many different styles and types of play. But what is it that actually makes these maps balanced(or imbalanced)? Is it even possible to quantify it?
First, before we look into what it is that makes a map imbalanced, we need to define the term “balanced.” For this article, I’m going to disregard any aspects of the metagame or current weapon balance, and assume that the T and CT sides are equally strong in terms of meta. Although meta can intensify already-present aspects of a map, if we’re looking at maps in isolation we need to disregard certain times in the game when certain weapons are more or less powerful(for example, the time in mid to late 2014 when the CZ was very powerful made the game super CT sided, but we can’t factor this into a map’s balance now) In simple terms, balance is how much a map favours either attacking or defensive play, or how CT or T sided it is. I’m also going to be largely talking about professional play here too; while general trends of balance do filter down to matchmaking and casual play, a lot of the time random mix teams have a tendency to be better on the T side in general, as it is easier to win a load of aim duels and overpower an MM team than co-ordinate a carefully crafted CT setup with appropriate crossfires, grenade timing, covering etcetera.
The main aspect that determines whether a map is T or CT sided is the difference between rotate times(or how fast it takes to go from one site to another) on T or CT side. As a Terrorist, a fast rotate between sites allows you to more easily play elaborate fakes, where you trick the CT side into rotating to the wrong bombsite. It allows you to more readily adapt to a failed take on one site, by making it easier to quickly change the site you’re attacking. An example of this would be Dust 2; it has a fast rotate from A Long or Short to B tunnels and vice versa, for the T side, but on CT if you’re in A site you need to run down to CT spawn and up B slope to reach B(assuming Terrorists have held their map control from the start of the round, which happens most of the time in pro play), by which point the Terrorists could have already killed one of or both the B players, taken the site, and the round is over. It turns out that this combination of rotate time difference and the current state of the metagame produces an almost perfect balance at the highest level, with parity between scores often seen at halftime in a matchup featuring most top teams these days. This is also seen on Cache, and Mirage(to a slightly lesser extent).
Contrast this with Nuke, removed from the map pool, and you find that for the CTs a rotate between A and B is quickly done through traversing the vents, however the T side has no such choice, and pretty much has to commit to a site in a take or otherwise waste too much time rotating. CT side can also take a safe route from A rafters down Heaven then into ramp and onto the B site, as well as using Secret via the outside area(although this last one does require some map control.) There is a similar case with the old revision of Train, where rotates between sites were disproportionately fast for CTs compared to Ts, leading to a sharp imbalance in halftime scores.
Another very important factor in map balance is the presence of a contested middle area. Certain maps, like Mirage, feature a middle that is hotly contested by both sides throughout the round. This is because the middle area, in Mirage’s case, is equally accessible by both sides; CTs can reach it by window, short and connector, and Ts can get there by top mid and underpass, but the AWP duel from window to top mid is often dictated by spawns. Furthermore Mirage mid links to both bombsites and allows teams extra room to, as mentioned previously, rotate between sites. When Ts have middle they can make a split take on either bombsite, but when CTs have it they can rotate extremely quickly to any site take being made by the Ts. As such this mutual contest makes the map more balanced; it offers an objective to both teams but doesn’t give one team an advantage in taking it. You’ll find a similar middle area in Cache and Dust 2, both of which are considered fairly balanced maps.
In contrast, Inferno has a middle area unlike that seen on Mirage or Cache. While timings for reaching it are actually fairly T sided, middle only links the T spawn to the A bombsite via a bracket area, and to banana. Banana is the most hotly contested area on Inferno, as opposed to mid, as it allows Ts to make a good B site take or pull off a fake(notice how normally middle control facilitates this on other maps), yet Banana has a host of CT sided attributes. It favours CTs in timing, it forces Ts into a narrow choke point that allows them to be grenaded or smoked off easily, and it can be smoked from the A site, leading to a situation in which a team can leave a single player on B and smoke off Banana constantly, while stacking four players on A, forcing Ts to either push through a smoke on B or face four CTs at A. Overpass is slightly similar in that its middle isn’t as important for taking control of, but it has no single focal point as Inferno does.
One last reason a map may be imbalanced is in key timings favouring one side or another. Despite Cobblestone actually having quite a fast rotate between sites for CTs compared to Ts, it is quite a balanced map. This is due to the huge inconsistency between the A and B bombsites in terms of viability. The terrorists reach the B long area(the main staging area for B site takes or fakes) long before the CTs do, allowing them to take more map control than is normally seen on maps, forcing the CTs to put more players on the B site. This means the T side can make more intricate fakes towards A, and CTs have to risk more in guarding bombsite B(introducing more possible mind games and complicated fakes). To compare, Cache is more fair in timings, as regards A main, mid warehouse and B main, both teams reach these areas at roughly the same time accounting for spawns(although CTs get a slight advantage each time, but this is expected even on the most balanced of maps.)
As a final thought, I’d like to stress that I personally express no bias or favour towards balance or imbalance; I have no grievances or especially strong love for balanced or imbalanced maps. In this piece I’m simply laying out why some maps are more balanced or imbalanced, however the connotations of these words are left to you.