Yeah, Kov has about 7 rounds to get Johnson outta there, or else I think Johnson would drown him late. On the night he stopped Galindez, I think he most likely does drown Kov late.
Apart from Roy Jones, I don't think there has been a fighter since the 1975-1983 class who could consistently stand in with that class.
I give the edge to Johnson as well. If Kova can't bomb him out in the first half of the fight, I think Johnson's relentless pressure wears on him by the second half.