So, I'll probably get drowned out in this, but when you touch on repetition, you really touch on a core element of games.
Repetition breaks down into a few components,
So, let's go from the top: Opportunity Cost.
-- This is a huge and rather important element of any repetitive action, be it quests, or grinding mobs, or spamming buttons that are all the same, etc. You can think of opportunity cost like "Investment"; and it ties a bit into iteration time. When you do an ANYTHING, any action at all, how does the player internally measure that action vs similar actions? Games are a constant chase after the most efficient path, and finding that most efficient path is going to require the player to try a lot of things, and feel the need to be rewarded for his/her time.
To look at some of your examples:
In Counter Strike, your weapons were a small part of your choice space, and the opportunity cost of those choices was a component of optimal path gameplay. When something is optimal in competitive play it is a "non-choice", and so doing it is a reflex rather than an action; this removes it from the "repetitive" mind-space. The real repetition in this game is killing people, taking objectives, and tactical planning, all of which are at the core of the gameplay, and all of which are HIGHLY dynamic, thus barely ever repetitive. When your core gameplay is dynamic and WELL EXECUTED, (By that I mean people find it "fun") then repetition isn't an issue so much.
Dota has a roughly one-hour opportunity cost on its champions, but the meat of the champions is their abilities, and how those abilities interact with players and those other player's abilities. The meat of the gameplay comes in small exchanges; each time you use a skill somewhere, attack an objective, a player, buy an item, use the courier, all of these are the meat of the gameplay, and they again are HIGHLY DYNAMIC. You can use a skill every few seconds, and using that skill generally feels really good (Except for with Skeleton King). Your gameplay space is inhabited by 9 other dynamic players all of whom you can't control and are always different. The map itself is just a static gameplay element which reinforces tactical awareness and strategic movement. By its design, and being highly static, it causes emergent dynamic gameplay (Fog of war, other people making uncontrolable choices, many objectives cross-map to cause people to move out of lanes, incentives for moving across lanes, etc.) The whole structure of DOTA is to incentivise players to move around, and create dynamic circumstances, thus preventing repetitive burnout. And you can always seek out a new circumstance, just go wandering around.
Smash Bros is again a highly dynamic game, where your skillset is chosen for a small period of time, but random items, as well as extremely low iteration time on skill use and the inability to control what the other players are doing makes it so every fight is different, and every encounter a fresh one. It's not about who you're playing-- that's a small choice. The meat of the game is FIGHTING, and the fighting aspect of the game is as rock solid as Brock's Onyx. The meat is not repetitive, so smaller, potentially limiting factors like Final Destination No Items 3 Stock Fox Only is not a gameplay choice-- it's just a setting. The gameplay is two Fox's waveshining eachother to death.
Tag Pro is addicting in part because of a high skill cap, but also because it's got extremely fast iteration time and thus low opportunity cost-- the cost of making any action in a game of Tag Pro is so extremely low, and can be altered almost immediately. Additionally, a loss -> back into game happens instantly as well, so there's no downtime or obnoxious waiting before you get back to the fun stuff. Again, there are multiple players, so you never go into the meat portion of the game (moving around the arena, triggering traps, earning points) and have the same experience twice. (This game without other players, for instance, would be complete garbage. Do you want to put a ball in a hole on an identical map five times? I sure don't.)