Honestly, you just summarised people's feelings towards most games. They all lose their spark after some time.
^ These, and this guy's sig...:
--- What determines whether a game is good is your experience every time you play the game, not the opinions of other people (unless you let it do so).
...pretty much sum up my thoughts on the topic so far. Oh and, no, the map editor will keep me around for at least another year if not longer. One of the major reasons I even bought the game. That alone will be enough to look back on and reminisce about.