Truth be told, I honestly don't think the Master Chief needs action scenes. A short scuffle here and a punch-up there, sure, but anything like the opening of Halo 5: Guardians, with Osiris just isn't the Chief's style.Remember,Chief as Spartan II should be superior in strength,speed than Osiris Spartan IV-s.But most of the time we see him in Cutscenes he appears slow like a RoboCop.
That should be true to a degree, however, the Spartan IVs are just about as strong and as fast as an SII while in thier GEN 2 armor. The GEN 2 is lighter, faster, and stronger than the GEN, as it amplifies the SIVs abilities to that of the SIIs in thier respective Mjolnir. However, during Halo 5, the Chief was equipped with his own GEN 2 Mk VI MOD armor.
With that said, the GEN 1 scales force fractually, meaning it increased strength as the user forces it to. This means the harder the wearer wills themselves to go, it will amplify accordingly. Which is why there are instances where the the user over extends themselves, often injuring them in the process. Like when the chief successfully out ran an attacking gunship while testing out his new Mk V Mjolnir, but also tore his Achilles tendon in the process
GEN 2 will only enhance abilities to that of a baseline GEN 1 Mk VI, which is still very impressive, meaning every Spartan IV is on an even footing with thier compatriots.
Locke's Hunter armor was a prototype variant, which could imllybthat certain functions could be overridden, or that it was a more improved GEN 2 system (Gen 2.5?) That couldve allowed him to go head to head against the Chief as his did.