It’s not like I think he is not a capable fighter anymore. There is no doubt that he is a very capable fighter. In addition to that, he is also over 40 years old. With 42 wins, one draw, and only one loss in his career, he has achieved a remarkable record. I wish him the best of luck in making it to 43
But yeah it's a different boxers, maybe GGG is knowing what should he do in the trilogy fight.
I don't think that he will play defensive in the 3rd fight. He already saw his mistakes specially in the first fight wherein he allow Canelo to control the championship rounds (of course the judges as well have something to do with him losing).
Perhaps GGG will be very aggressive and he should take advantage of Canelo being a slow starter. But he should be cautious as well in the latter rounds as this is where Canelo usually score points. GGG needs to be consistent for full 12 rounds and not allow Canelo to be comfortable.