My acquaintance with the series began with CS 1.4, which I played on my cousin’s computer, and then I bought myself a disc with the game and played for a long time with bots, in a club with friends, then we played 1.6, later I got a fast Internet and then it was released CS: Source, in which I was a member until the release of CS:GO (I played it from beta). In other words, I have something to compare with.
CS:GO is a kind of extract from everything that Counter-Strike used to be, but dressed in the wrapper of a modern military shooter and seasoned with expanded competitive capabilities (now you can drag not only on one specific server, but also show everyone on the network what a high rank you have).
The graph was corrected, bringing the interior to reasonable detail, though it’s unclear why, because the world of CS has never been about realism and convincing surroundings. For example, imagine that on the Quake map q3dm17 in some Quake 5 they will add trees growing everywhere, against which players will constantly hit their heads when jumping, and a bunch of all sorts of tinsel to “convince” this competitive map. The situation is the same in CS:GO, although in fairness it should be noted that the impact on gameplay is minimal.
We introduced skins that particularly crazy players buy for several thousand rubles. Well, that's their business. I am glad that CS:GO is an ideal example of the harmony of the game and microtransactions; for a thousand rubles your body armor will never become thicker, and the sight will not aim itself. But sometimes trunks fall, which can be sold on the gaming market for a symbolic 10-20 rubles, which can then be spent at the next sale without any investment of your own funds ;)
To sum it up, CS:GO has filled a niche with its release “modern counter”, displacing Source from it, since it is essentially the same thing, but with many new and convenient functions. If you like Counter-Strike, but are pretty tired of 1.6, take CS:GO.