In an interview with Polygon, Sledgehammer Games stated that Exo-suits in Call of Duty: Advanced Warfare will be upgradable after each campaign mission. For each level, you earn points depending upon how well you play. End of each level, you will be able to upgrade your exo suit.
Speed, mobility, agility, reload, etc can all be upgraded. Glen Schofield says that you may have to play it more than once to unlock everything in campaign.