I love how the Halo 4 & 5 armor looked, it started to go in the direction of evolution and leaving past armor for past in game movements and mechanics like the halo 1,2 & 3. In the new Infinite trailer showing an older art style armor really just leaves you like, why... It takes some of the badass that the armor gives and even kinda tells us that doesn't even have the propulsion system of the Halo 4 & 5 gave us, why go back to the same?
On an aesthetical level those "propulsion systems" have always been there though. Remember those boxes on the back of Chief's shoulders in H2 and 3? This is what you're referring to basically and aren't exclusive to H5 at all. quite the opposite. They have been there since HCE in fact, even though they used to be build in like a back-pack. Since H2 those are actual separate elements on the back and all Mjolnir Assault Armors in all Halo titles have ventilation holes on the exact same spot as well. Including Hi, just look at his back!
Therefore no, the art design doesn't tell us anything about movement mechanics, because you could apply the exact same animation and effects on the the new armor too, as well as older Halo games prior to H5. Those are just different interpretations of the exact same in lore systems, even placed in the same position. It just happens that H5 actually used them in gameplay and not just for cut-scenes! :P