Why was he able to actually get to the QB so rarely? Or make any plays at all?
Putting sacks and pressure aside do you guy realize that last year Robinson produced 15(FIFTEEN) tackles.
Coupled with his 3(THREE) sacks he actually put a guy with the ball in his hands on the ground less than 2 times per game.
I see the tremendous explosion off the snap but how the hell was he so unproductive?
Yep, I look at QB hits + sacks / pass rush attempts, and Robinson didn't stack up well there either, so it's not just a lack of sacks. It's a lack of actually getting to the QB. Latu, Verse, Turner, and Braswell all got to the QB at a significantly higher clip (in that particular metric, they all stack up really well to recent Edge classes).
Robinson is a bet on talent and development. And, the talent is significant, but the questions/concerns are, as well. I think most agree that your perspective on Robinson hinges on how you balance those.
Plus, as Largo noted, his relatively small, so his situation will be important.