I for one, believe its close to useless.
-- You will rarely achieve any kills from this effect. --
Its very circumstantial. In several cases it may even get YOU killed. For example, Katarinas ultimate becomes activateable when near a stealthed Teemo.
-- It still takes 3 seconds to stealth even after the latest patch saying it will take only 2 seconds to stealth. --
-- 'Element of surprise' is redundant. --
3 seconds is not enough time to get you anywhere offensively. It will only get you cocky and get yourself into a situation you might regret while trying to make maximum use of the bonus attack speed duration.
The following suggestions are replacement alternatives to the secondary benefit of 'Camouflage'.
Suggestion 1: Three seconds after being stealthed, your next attack deals 100% more damage.
Suggestion 2: While stealthed you recieve 50% damage reduction. This effect lingers for 3 seconds after unstealthing.
Suggestion 3: When your health drops below 25%, you automatically become stealthed for 1.5 seconds. During this time, you are still able to attack without revealing you whereabouts. While you are untargetable, skill shots are still a threat. Let's not forget about oracles also.
This at least gives him some sort of defensive capabilities.
-- Recalling now stops Teemo from stealthing now --
I thought that's what oracles were for. This is just another reason why Teemo's Passive as a whole is completely pointless. He is very easy to kill already, especially since he heavily depends on offensive equips to keep him adequate in damage output. Why take away this unique capability when it 'can' be countered?
So, what do you guys think?
On a side note... I believe Blinding Dart should explode of impact in which it effect adjacent enemy champs for half of the Blind duration.