Locke is a highly trained ONI specialist whose current mission is to hunt down the Master Chief. In other words, he is a massive exception to the norm. Most Spartan-IVs are just Marines in fancy armor.

All Spartans are highly trained. They aren't going to exclude abilities from the rest of the super soldier force. This "marines with armor" idea is completely false. If you do any research on them you will realize that their canonical abilities are on par with the Spartan II's in armor. Not anyone can be a Spartan IV, that's like saying anyone can be a navy seal. The arbitrary resentment that the community has is unwarranted and unbacked.

Alright, yes, after doing a little research, you're right. But my point about Locke still stands. He's a special operative of ONI. He's going to have superior training and such. When it comes to the hatred of the Spartan-IVs, I think it's a case of bad introductions. The first time we really see how Spartan-IVs act is in Spartan Ops, and Majestic was far from a good example of the average fireteam. They were insubordinate, juvenile, overly-dramatic, and downright idiotic. And Palmer…well, she wasn't a whole lot better.

While their goal may have been to make the IV's more social than the II's and III's, I have yet to understand why they chose to make them seen unprofessional. And Palmer just can't get her shit together. As for Locke, I can imagine he'd know more than the other Spartans in terms of ONI directives and such. But when it comes to combat effectiveness, I don't imagine a huge skill gap between him and say Buck.