Defenders always have situational advantage; when I say "offense should always trump defense", I'm speaking purely on mechanical terms--though it's not a terrible philosophy to have when approaching the problem holistically as well--especially in eSports. Attackers winning will always be more exciting than defenders winning. Games like R6S give offense increased firepower and utility to make up for this difference; CS has plenty of utility options as well as high movement speed.I agree mainly. Not the last bit though. A well designed shooter should see offense and defence being equal and down to the skill of the player. BFV for example - you can camp and do well but it takes a skill of subtly moving position and reading the fight. But equally you can be rushed. Attackers can use angles to hide the assault and also in game mechanics like smoke. The problem with MW is as you say that the map layout, visual design and pacing all favour people watching lanes.
MW gives defenders mechanical advantage (long ADS times, low TTK, low strafe speed), situational advantage (sound, light conditions, less angles to cover), and utility advantage (mines, Claymores, perks to place more and recharge them). It's the holy trinity of camper design, and it's awful.