How about everyone takes a step back and looks at it like this
We haven't actually seen what either character can do with their new power-ups.
Until then, we can only make assumptions based upon what we do know. Now, my guess is that currently they're close to being equals. Both Ichigo and Kenpachi went down last time. Now, Ichigo would be around about 15 - 30% Stronger than Kenpachi, since we haven't actually seen what Kenpachi can do now that he knows the name of his sword.