Stealth mechanics

So since the change to stealth not being seen by sweeper lens or pinks (aka control wards). The game has heavily favored champs like Evelynn, Akali, Kha, Shaco etc. Most high elo players(Master+) would be inclined to agree. As it stands there's no counterplay to the stealth mechanic, which is unbalanced. Personally I'm not sure why this was ever changed.