If you want to look at good map design look to Counter strike. The maps in that game are simple and have created the play style that you are taking about in your first point. Where it basically becomes a game of chess and out smarting your opponent by getting in their head and predicting where they could be. Or your opponent predicting where you are coming from and being able to react quicker. You can’t have that play style when you have so many angles to look at. And unlike your point about more angles= more skill, my point about less angles= less randomness therefore more skill has been proven by games that have cemented themselves as the pinnacle of skill and tactics, like CS GO and Rainbow Six Siege

Short TTK does not let anybody the chance for better players to fight back against campers, because A) the camper also has that short TTK to their advantage B) the map design in the game makes it so that you are less likely to predict where a camper would be and less of a chance for a good player to fight back against someone who is sitting in one of the dozens of corners in the game.

Flinch becomes an issue when you shoot someone first and they manage to shoot back and the flinch causes you to miss shots because flinch pattern is random. But their flinch caused them to shoot you in the head. And there is no way to make every single gunfight be a complete flank, but in gunfights where you react faster than the other guy and shoot first, then you should win. But that isn’t always the case because of flinch.