Teemo as the ADR of the team

His abilities aren't meant to be played as a potential ADC, and his range isn't a plus, either. Though people still play it on this role because it can and will be a pain in the *beep* with his annoying capabilities, haha.

You would have more chances of winning the game if you played it like it was initially meant to: AP Top bruiser or Mid Lane mage ( though this one is kind of raged by people on some servers, since they don't consider it pertain to the current meta)

 

I don't think Teemo really fits the ADC role. There are a lot of better champions that do his work much better than him (Vayne for this instance).
It's kind of gimmicky to play him as the ADC.

 

I know that Teemo used to be run as the ADC of a team every now and then. His blind was pretty strong in the lane when basic AA ADCs were used more often. People like Ashe, Caitlin, Tristana, etc. But yeah, his range is the main problem. It's much too easy for just about anyone to smack Teemo down and knock him out of lane.
Also his ultimate is much too strategical for a typical ADC. Most of them have lots of damage on their ults, or incredible utility (Corki and Ashe come to mind here). Teemo's range also really hurts him in team fights, as he needs to get pretty close to the enemy, and in doing so is close to throwing his life away-- Or at least making it hella difficult for his team to defend him.

 

Teemo can work as an ADC in lower tiers but you have to know what you're doing. There are so many other champions better for the role due to their kit but a properly played teemo can be quite the asshole. lol. As long as you have a strong support in lane, you can make it to mid game, you're usually good.