Well it's more realistic, before on defense you could hit unrealistic laser slices that would instantly turn the point for you. Does that happen in real tennis when a guy is 10 ft behind the baseline? Of course not. So all in all it's more realistic.
Sounds like a lot of you were slice cheesers, which this update finally killed. The slice was overpowered anyways, how many slice FH winners do you see in a real match? In TS4 before the update the slice FH was one of the strongest shots, lol. Now slice is actually a strategic defensive shot instead of a powerful offensive shot. I like it.