Most draft picks are gambles. Not sure what you're getting at there. Percy Harvin was a definite gamble, as well as Adrian Peterson. Look at how many players never pan out at all. Our how about Donald Driver? Clifton? I could keep going on. Fact of the matter is, most players are a gamble, and you hope they pan out. Thompson is NOT the only one that "gambles," in your words.
Now, I will give you the Harrell pick (thank you NonStop for finally correcting that spelling). I didn't like it at the time and still don't. However, one bust of that manner is acceptable with as many hits as he has. I can definitely live with it. I think Thompson has learned from it as well, and that's all you can really ask.