An idea for an armour ability is the flight pack.
This allows the user to fly as if they were in a banshee in burts. The minimum speed is sprinting speed and the max is double that. Users can only use secondary weapons with lowered accuracy if they are using this ability as if they were sprinting but can board vehicles of they hold the board button whilst flying into a vehicle. With vehicles such as the ghost or warthogs (anything where the driver is not fully covered) the driver is not hijacked but is ripped out of the vehicle and the affects of being hijacked still happen. Users can hover with this and use all weapons. Users take damage if they collide with things and that damage increases as their speed increases. Scope cannot be used whilst this ability is being used.
For sprinting speed it is a 20 second burst and for double that it is a 10 second burst. It has a large turn circle and that increases as the speed increases (scorpion turn speed). This armour ability cannot fly directly up and uses the controls and the flying angles of the banshee.
I thought of this as when Halo 4 was announced, I thought the thruster pack would be like this but ground based. Also I missed the feature of the ability to hover like the Halo Reach jet pack.