Dev mode at this point is only useful for emulators, if you're referring to a "cfw" then it's very unlikely without some hardware mod, it'll probably be just like the 360 where you'll need to modify the board in some fashion, or maybe dev mode research may lead to something
you can run emulators, you cannot pirate or mod games or run cfw, some sort of hardmod would likely be used if full hombrew access is achieved, I won't say softmodding is %100 unlikely but don't count on a "flash drive mod" for xbone to happen