Makes sense, hope he does well. Would like to see him as a WR option! Yikes.I don't think it is a toughness factor. Some people have a more natural feel for things like positioning their body, reading a defender's body movements, deceiving with their movements, etc.. It is hard to quantify these things because they largely take place within the mind, but they matter enormously. In college, Hock had a better feel for creating space on a route and for making yards after the catch. Fant has more ability to run by someone. Both are important skills, but I think Hock's will result in a bigger, immediate impact.
I thought it was interesting that Fant was essentially the same size as Hock (2 lbs lighter), with longer arms (33.5 vs. 32.25), and greater bench press strength (20 reps vs. 17 reps). Yet I don't think there is any question as to who was the more effective/consistent blocker. The game of football goes well beyond measurables.
In one of the other draft threads, an analysis of Fant was posted, and it noted that blocking should actually be one of his strengths at the NFL level. He is big enough, he is willing, and he shows good technique at times. But just like with getting open and catching, his consistency can be improved. I feel he tends to overreach and get off balance at times, resulting in some pretty bad whiffs. But when he gets in position and gets engaged, there is no reason he cannot be a weapon blocking as well.
Long arms are a big benefit, other than pushups and reps for 'strength" measurements. Then the "long stroke" is tougher to accomplish reps.