I have 8 playthroughs of ME1, 30 of ME2, and I'm on my 18th run of Mass Effect 3. I've chosen most dialog paths at one point or another. That said, I still occasionally get dialog I've never heard before. Or, I didn't remember some dialog given how old the game is and how many playthroughs I've had. They blur together at this point.
But did you change decision path just to try something new or did your change because of who you're now vs when you first played (I played all of them at launch but no more than 2 playthrough (and only to get to max level in ME1 given how bad the combat and Mako mechanics were).