@Meddler: Why don't Rioters distinguish between stealth gameplay & stealth mechanics?
Riot has attempted to create two categories of 'Stealth': Invisibility and Camouflage.
Invisibility can be thought of as 'tactical' stealth and is the more common of the two mechanics. Invisibility effects don't last long enough for its users to move from one lane to another, but are well-suited for combat maneuvering (whether that's within a fight or starting one). Champs like Wukong and LeBlanc possess this mechanic.
Camouflage is what we call 'strategic' stealth. It's strongest when used to get around the map unseen, moving from one victim to the next. Evelynn's had this mechanic for a while, and we're extending it to Rengar and Twitch as well.
I almost never hear Rioters talk about stealth as though it is a type of gameplay or a mindset - it's almost always spoken of in relation to being an ability in a champion's kit. It seems like Riot trying to classify stealth into two different things with different definitions indicates confusion about what stealth is, and that confusion has spread to the League community. This is due, I think, to Riot's definitions being fundamentally flawed.
Stealth: (stĕlth) n. cautious and surreptitious action or movement; adj. the quality or characteristic of being furtive or covert.
With that definition in mind, every champion in League of Legends can be a 'stealth' champion. This definition is is exactly how the pros play League of Legends, despite rarely playing any of the 'stealth' champions. Is it not true that Garen is being stealthy if he has taken up a position in a brush and the enemy has no knowledge of his presence? Is it not true that a champion is using stealth if they concealed behind terrain, having vision of their enemy but not being visible themselves (due to the Fog of War)?
Invisible: (ĭn-vĭz’ə-bəl) adj. not visible; out of sight; unseen; hidden from view; impossible to behold; imperceptible to the eye.
Brush provides invisibility. The Fog of War provides invisibility. Certain champion abilities provide invisibility. Camouflage is invisibility. Invisibility based on proximity with a longer duration than others, but invisibility nonetheless. And invisibility is a prerequisite for stealth. However, one can be invisible without being stealthy.
In my League journey, I've dug deep into stealth games as it seems like invisibility is League's least explored design space, with vision coming in close behind. And I believe I've found out how stealth and invisibility have been conflated in the gaming public's mind.
http://vignette4.wikia.nocookie.net/wowwiki/images/f/f8/Ability_stealth.png/revision/latest?cb=20051006101655 Stealth, the WoW Rogue ability, rendered the user functionally invisible in PvP environments. And League was being developed when WoW was at it's height, yes?
Especially interesting is that DotA and DotA2, which were both born from Warcraft 3, featured 'stealth' mechanics, but it was called, and still is called, invisibility.
This will probably get ignored or downvoted, but I'm still waiting for Riot to really embrace stealth and vision as key pillars of League.