Teemo rework idea
Change his E to be stronger, but only count for the next 4 basic attacks, and stack the poison's effects. Give him a down time where he is more vulnerable, but make his trading potential a little bit stronger. His E is free extra damage, and that is a bad thing for Teemo, as it is hard to make it stronger without breaking the champion.
Make his R visible for 1.5 seconds before arming, and it can only take one basic attack before it is destroyed. However, once armed, Teemo can shoot his own shrooms with basic attacks and they will trigger. This will let him utilize the full zoning effect of an armed shroom, but makes it harder for him to simply throw one at his feet when fighting. Remember, his blind will prevent people from destroying it before it arms, so an R into an immediate blinding dart can be a potent combo if you're dueling.
That's my little weasel