Depends on what point in their careers you look at.I always get a bit annoyed when Hayden is described as an excessively aggressive opener. I grew up with him (as in watching him on tv) and while he would walk down the pitch and hit big balls and have an overall aggressive demeanour he left almost everything outside off-stump and young me actually found him boring at times. He barely even had a cut shot.
Langer was often outscoring him in opening partnerships in fact
Hayden slowed down in the 2nd half of his Test career. Guessing it coincidences with bowlers finding more chinks in his batting. His peak strike rate in the first 51 Tests was 63.5 vs a strike rate of 56.55 in last 52 Tests.
Langer only sped up. Strike rate in first 52 Tests was 50.36 vs a strike rate of 58.17 in last 53 Tests.