Contrarily, I've gotten a ton of play out of LoL; given the player-vs-player format, although games follow a general pattern, it's a competitive game of skill and so it's not really 'monotonous' the way that single-player games can be.
If you don't like the genre, sure, it won't be terribly exciting. If you're interested in the game, and becoming good at it, and learning it in and out until you're competitive, there's a lot to it, and it's constantly being updated -- the designers are not passive in any sense.
The whole leveling thing can be a pain, but if you don't play it much, you'll never get out of the newbie league and you'll never really play against skilled competitors. Someone who played it for less than a week is going to have as much insight into the game as someone who played something like World of WarCraft to level 30; you can know whether or not you like the basic gameplay by then, but you won't understand (or anyway, have experience with) the nuance of high-level play.