OK, I appreciate the fact that you are dedicated to your chosen champion.
That being said, the only times that I play Teemo are when I want to ruin other people's fun. Which means I play him once a month, if that, since I'm not a sadist.
Teemo still fulfills niche counters in toplanes (Olaf, and other pretty much melee only champs with some poke). The reason he was nerfed (I don't see why the Shroom nerf happened; it wasn't OP, just annoying) was because Runaan's AP/AS Teemo was horrendously OP if a teamcomp had enough peel.
Still, he falls into the "unfun champs" bracket. His counterplay is absurdly simple, and his gameplay is very low skill floor, low skill ceiling.