This entire time linearity meant something else, worst thing though, I wrote "here hoping you don't mix linearity with words monotonous and repetetive again" (because you did that once already), twice, and you couldn't simply say yes and saves us a lot of trouble.
By that logic of yours near every FPS is as repetetive as it gets (not just COD and Halo because guess what, you do exact same shit in other FPS), and not just that, but racing and fighting games as well. In first you literaly just race cars and in second you fight, that's it. Let's just forget that both Halo and COD offer dozen multiplayer mods, in each you have different objectives where difficulty, scenario, your role and how you handle your opponents are completly up to you and other players. I'm wondering does that go under monotonous and repetitive? Wanna know what's repetitive, Donkey Kong Country and Kirby games. You literaly just walk down one path and jump on/suck in enemies, how about that, and here you thought Nintendo doesn't make repetetive games.