@Meddler Can we get a patch dedicated to Reworking stealth?
Stealth has basically been regarded for most of it's entire lifetime as a toxic mechanic, which has caused a tonne of characters that use it to have been shoved into the mud and left there out of fear of being overpowered and broken, lets have a recap shall we?
Released broken and then nerfed to oblivion, hardly any in-between currently VERY VERY VERY meh
Broken on release, nerfed to oblivion then buffed back, becoming a niche pick.
Always flipflopped between broken due to her insane damage and useless due to her squishiness.
Broken on release but was kicked into the mud by crushing his lategame, not received a buff since april of last year and that was just an armour buff, his last big buff was March of 2012, fear at it's finest.
Oh Twitch, probably the most interesting ADC, one of the game's first hypercarries, thrown to the ground and left to rot as one of the weakest ADCs in the game, and would you look at that, he has invisibility!
I don't think this one needs too much of an explanation, it's only been recently that he's even started to show his face at all due to how weak he was before.
Generally regarded as the healthiest Assassin in the game, a large amount of his power budget is in his ult which grants invisibility, and talon's not seen the light of day in quite the while.
The only ones that i'm not really counting are:
As they either are 100% clear in the fact they're invisible (Wukong's clone, Akali's Shroud, Teemo has to stand still), although a point could still be made for Wukong and Akali.
Now why is this? Other MobA's have stealth mechanics that are completely balanced, why is league different? Well to put it bluntly: Itemization.
At the moment there are only 3 ways to reveal stealthed units:
Raptor smite (But you have to have walked near a ward first)
This is an incredibly low pool of itemization for stealth and has lead to many champions being gutted simply due to the shallow variance in ways to deal with them, and it's only decreased since the removal of Oracles, 
and the map restrictions of
means that until an update dedicated to the revamping of stealth you will have basically left a large amount of champions near useless.