This is just a random thought of mine, but a lot of the time the rage does not come due to the change, but the reason for the change.
If a developer states "We're going take out the RPG elements to more people will like us" or "make our title more accessible to the casual gamer" an instant red flag goes up, it's tantamount to a slap in the face, they're stating "hello fans of our series, you're not profitable enough so we're going to focus on appeasing these other people who didn't buy the first game".
A good developer will not say these things, the changes will speak for themselves. Valve made several changes to make Portal 2 more accessible to the casual gamer, but they didn't cheapen the core game play for the experienced fan, and through it all the only reasons they gave was "we're making an awesome game".
If a developer states "We're going take out the RPG elements to more people will like us" or "make our title more accessible to the casual gamer" an instant red flag goes up, it's tantamount to a slap in the face, they're stating "hello fans of our series, you're not profitable enough so we're going to focus on appeasing these other people who didn't buy the first game".
A good developer will not say these things, the changes will speak for themselves. Valve made several changes to make Portal 2 more accessible to the casual gamer, but they didn't cheapen the core game play for the experienced fan, and through it all the only reasons they gave was "we're making an awesome game".