Well we are talking pre right now and I meant that kenpachi is obviously a tank and therefore it would have been hard to give him enough punishment to stop him. And I don't see how pre skip was stronger considering kenpachi diced the espada with the strongest hierro and beat yammy who is supposed to be the strongest to a pulp(with byakuya I think).
Now that Kenny is stronger than Unohana and has a shikai(which is bullshit, because it's been 7 months and they still haven't shown it yet), he probably shit-stomps even post time-skip Zoro. He just can't deal Zaraki the punishment he would need to in order to bring him down. Zoro's strong, but he would lose to Dangai Ichigo instantly, and it's probably not too far fetched to claim current Kenny to be stronger or at least as strong as current Ichigo.
__________________
"Why is everybody so ****ing stupid?"- Kim Jong Il, Team America.