Having complex mechanics on one part of the game does not make the game a non-arcade. It is arcadey on the sense of how it is played. You're playing in small enclosed areas and it is extremely easy to pick up the game. Of course, you can learn the spray patterns but it is not at all required to play the game.
The battlefield series in turn, while not really realistic, has way more moving parts in it thus making it less arcadey.
I don't think map size has any factor in "arcadeness". The degree to which mechanical complexity exists and interacts with different aspects of the game is. CS traditionally has a huge skill gap where other games don't have any, e.g. in Battlefield movement is relatively irrelevant; so to get kills, you can largely just rely on aim. In CS, only having aim will not get you many kills at all (the most obvious issue being that you will simply miss most shots, irrespective of how well your aiming ability put the crosshair on the opponent).
> The battlefield series in turn, while not really realistic, has way more moving parts in it thus making it less arcadey.
I think you vastly underestimate just how complex CS is and how many gameplay elements are intermingled to make plays happen at higher levels of play. As a long time player of both BF and CS... BF has more "stuff" and more things going on at the same time (mostly due to large number of players and vehicles), but is definitely not the more complex game.
On top of that, CS even at medium levels of play, is more about game sense (strategy, understanding your enemies positioning and reactions to stimuli, timing, ... game sense in itself is a vast sea of complexity) and communication than raw mechanical skill, although the latter can to some extent compensate for the lack of the former. At high levels of play, purely mechanically skilled players are... worthless.
The battlefield series in turn, while not really realistic, has way more moving parts in it thus making it less arcadey.