I got Kai Banished 13 times in this "duel" before I got bored of the Time scenery and left. No timestamps, but I got Kai Banished about every 5 combos, which is ~15 seconds.
Putting a channel on it would prevent it from being spammed so excessively 1v1 as it would then be able to be interrupted. Would leave the teamfight use largely intact. Or just make it so it cannot be used consecutively on one target.