Originally Posted by JP
The guy who designed Mystique and applied the makeup retired sometime after x2, which is why mystique in x3 doesn't look as good.
This was the answer I was looking for. I didn't know this. Thanks!
That said, considering Jennifer had a negative reaction to the paint and/or prosthetics (blisters, etc) when Rebecca's only bad experience with the material was having a hard time removing it thoroughly, it was obviously bad call on the production's part not to seek out the original team, or at least use the same techniques.