Based on last night, mid-60s seemed to be his range on kickoffs, pretty consistently -- except for the one he kicked from the 50 which he couldn't get to the back of the end zone and the opening kick off which he got 70 yards, to the goal line. (His kicks were 70, 68, 65, 63, 63, 64, 62, 55.) That's not enough. You need a guy who can give you a touchback at least occasionally. When every kickoff is returnable, barring wind or a penalty, you're just asking for trouble over the long haul. To have a guy who cannot even reach the end zone on kickoffs is not a long-term plan.
To me, though, it looked like his kickoffs were very very flat and extremely returnable. I don't remember each one, but the Steelers routinely were getting 25 to 30 yards on the kickoffs, and came close to breaking a couple much deeper but for some good tackling.