It would be really nice to see sneaking in an indie game...so i would go for the stealth if i was a dev
Personally i think that stealth would be hard to implement and balance in a 2d environment. Especially in regards to multiplayer.
Their have been a few games now to include stealth in 2D say for example mark of the ninja. I think the easiest way drop stealth in starbound would be to let people hide behind furniture objects. It obscures you in multiplayer and gives a nice effect for single player.
I don't know, it works quite well in Mark of the Ninja, which in turn works a lot like MGS in 2D (sounds have a circular, as opposed to spherical radius. Also, cones that represent the enemy's POV). But putting this in starbound might just be a whole lot of work. I mean MotN is an entire game based around just that mechanic. For multiplayer, there the sound and the line of sight could determine other characters' sprites' opacity or something.
Otoh, mark of the ninja doesn't have to take into account an environment that the player can himself modify and completely reshape on the fly.