Henry is carrying the ball well beyond the amount of any Alabama RB before him. I don't have the time tonight to look up exact stats, but surely we can agree on that.
He's had tons of carries when the game is clearly out of hand. In previous seasons we've had our #3 guy get legitimate carries in those games... Both Lacy and Drake became fan favorites early in their career in that role... Finishing blowouts with impressive runs.
Obviously the depth isn't near as good as in those seasons, but your reference to the way the staff has handled starting RB's in previous seasons probably works in my favor more than yours. I haven't done the math on it, but I don't ever recall the starter averaging 24 carries, and still getting touches in absolute blow outs. Maybe I'm misremembering though.
I think it's more likely that Saban is anal about how the team finishes the game, even in a blow out, as to why Henry is taking so many snaps. Hence the "perhaps" word usage... However, Henry is probably unprecedented territory at UA with his work load and the blow out carries are somewhat head scratching.