I don't have any evidence or backup info but just from interviews it could be either? Stealth/sneaking or fullout rambo style. or both. Just what I heard though.
I'd say it's more stealth-based but different situations call for different approaches, plus all the extra boosts your suit gives you are pretty sweet and let you play the game differently.
From what ive read, and from the level 1 demo, you can go about it in many different ways. You can run in guns ablazing or use your surroundings and be a stealth ninja.