Now that DFT is gone Teemo's mushroom damage potential is severly reduced.

No. His abuse of Aery and Kleptomancy have just shifted the power from his shrooms and midgame to his auto attacks and Q. There is plenty compensation, one might even say too much.

good.

I walked into a mushroom and Aery hit me from half way across the map.

Aery?

-on a side note i saw DFT and immediately thought DFG and was like "wot"-

I'd venture to say that even Press the Attack and Lethal Tempo are good to have on Teemo - it all depends on what kind of Teemo you're trying to play - the "across the map shroom kill that's based 100% on luck" or the "consistent damage outputter in teamfights".

you should see Lethal tempo Teemo.