Locke isn't boring, though. Nightfall Locke might be, but Spartan Locke is just professional and restrained. Based on the cutscenes of the first few missions he understands just how important his role as the leader of Osiris is, and there's a clear sense of acuity and rationality in all of his responses - note how much he pauses when he gives answers. He's also got the weight of ONI knowledge on his shoulders, and while he's not entirely unhinged, mind you, you can clearly tell he's become a different man after working for ONI for so long.
His fighting style is also basically the coolest out of any of the Spartans we've seen in the games. It's hard to see, but the first time he stabs Jul is when he thrusts under his sword, and then he's got the two following. Probably worth clarifying: Locke managed to down the supreme leader of the Covenant remnant so quickly because he stabbed Jul in both of his hearts before getting him in the jugular. There probably should have been a lot more blood in that scene, but it explains why Jul dropped dead almost immediately.
