Higher streaks pass 7 would make it more rewarding to get a new killstreak to use for those that are completely wild.
Maybe some more nanosuit killstreaks besides max armor that is not as good as max armor but gives like a stealth advantage something like that for armor power and stealth, or maybe more ceph alien based killstreaks like a ceph gun turret ect.
Post what ideas you have for killstreaks that crytek might add