The most common justification for nerfs, balance changes, new features, and changes to old rulesets is that “the players aren’t playing as intended.”
The first one has obvious basis for commercial ventures, and the latter is likewise obvious. The middle one–a good example is Motor City Online. Because of how the game is designed, there’s more advantage to running the oval tracks over and over again for points and cash than there is from actually playing the full range of offerings the game has. This makes the game less fun for everyone, IMHO. I don’t think there’s anything wrong with trying to rectify that, and even applaud the effort, even if it is definable as “fixing it so they play as intended.”
I guess my key point is this:
Players will do things that are not fun, because we the designers reward them for doing it. And then they bitch mightily. But if we reward them enough, they keep doing it. Even when we tell them to stop and go *have fun* they won’t, by and large.
So if people aren’t playing as intended, it’s because your game mechanics are broken. You’ll just have to assess whether the way they are playing is more or less fun than what you had hoped. Often, it’s MORE, in which case you should embrace it. I think that The Sims is practically a poster child for this.