I remember someone (probably here) saying that the Shadow of Mordor/War "Nemesis System" could have become a widespread gaming system similar to how the unique mechanics of Dark Souls games became an entire genre and now there are all kinds of games that use the system and tinker with variations on it to great effect now called "soulslike." But because WB or Ubisoft or whoever made a show of patenting the system (and apparently won actual lawsuit challenges to it?) there is no genre of "shadowlike" or "nemesislike" games. That it was a clear example of a patent actually depriving us of an entire potential genre of games.

edit: I swear I read this whole thread before commenting but I missed EllenKelly already mentioned it. And yes, it has been discussed around here.