Who are the "dog" heroes that player should NOT invest in?

I always keep up with the best combination of heroes for A and B teams. Then there are also alot of middle-tier heroes who aren't bad, but aren't great except maybe at early stages of the game. What I'm wondering now is who are the =worst= heroes? Like instead of your top 10 list, what are the worst stinky dogs at the bottom of the barrel?