Get rid of sprint, advanced mobility and armour abilities
You never needed these gimicky features back in the OG Halo games because of intelligent map design and the use of all the neat traversal tools. Back then, Bungie made the use of: Teleporters, mancannons and grav lifts, vehicles and equipment. These tools to move around not only made the games more fast paced, but also added a layer of competitive strategy to them.
Halo 4 and 5 replaced these cool gameplay tools with armour abilities which are not only a detriment to the core Halo gameplay experience, but also rip the soul and creativity out of any map 343i decide to make.
The identity of the Halo franchise is at risk here. 343i seems to have realised that we want the classic art style back, but I hope they have also realised we NEED the classic gameplay back too, otherwise Halo Infinite will just be another disappointing installment in my favourite video game franchise.