I don't think there should be any debate regarding his ability to break tackles and pick up the YAC and tough yards overall during his carries. He happens to be a hard-nose back that doesn't shy away from contact. He has enough speed to hurt the opposition when he gets into the second and third levels of the D. I agree with the opinions that feel he has to get more carries per game. It's him and the other backs, who aren't bad, but he's the guy. Run him.
As for his poor blocking, It would be counter-intuitive to say it is a result of him shying from contact. Rather, it appears that he doesn't know the schemes and who likely is freed up defensively that he would be responsible for or that he is having trouble processing and/or reacting to engage the block. Thing is, he's going to be a third year player. If he hasn't learned it by now, he's either learning impaired or this facet has not been sufficiently repped or reinforced properly. That he has no problem hitting the proper hole/crease leads me to count on Seider to bolster the pass pro piece ;)
When this is rectified, a good back will become elite.