Yeah, C&C is about making your decisions matter, and it CAN be pretty obvious if it's only an illusion (try playing an evil guy in NWN2 for example). While in games like WL2, PoE, FO:NV and obviously TW2&3 (haven't played them so I'll take your word for it) you will get a sense of "this happened because I did that". You don't have to play through a game several times to experience that.
Now, of we're talking more random things like killing someone who could've shown up later in the game otherwise, that's a different matter. And those things can be fun too, but it's not what I would call well implemented C&C.
Now, of we're talking more random things like killing someone who could've shown up later in the game otherwise, that's a different matter. And those things can be fun too, but it's not what I would call well implemented C&C.