Complexity refers to the number of factors that effect game play at any given moment; skills, equipment, status, NPC reactions, etc. The Witcher 3 was not even close to this level of complexity.
lol, npc reactions. they are mostly non existent. just standing there waiting for some script even when i attack them. half of them are usually trying to walk through the building wall or are stuck in stairs/doors. complexity my ***.
skills? equipement? - canāt riposte with anyrhing other that log sword, broken stealth, etc. do you want me to continue. this is broken product with empty non responsive world. not even close to witcher.
and every other patch will break the game more. 1.4 even the main quest line, or even the feature that it adds 
You obviously didnāt get very far in math so let me spell it out for you. You count the number of skills and multiply by the number of different equipment, multiplied by the number status effects and you get the number of possible permutations. Add to that the number of branching plot paths and you get an idea of the complexity of the game. I enjoyed the witcher but it dosenāt really compare.