Jarvan IV Passive Buff

Jarvan IV's passive 'Martial Cadence' currently has an on-target cool down of 10 seconds at lvl 1, 8 seconds lvl 7 and 6 seconds at lvl 13. and deals 10% of targets CURRENT health as physical damage. In sustained fights, this passive isn't all that useful and you only get like 2 off in an extended skirmish also by the time it is back up the target is already at very low health meaning the damage is significantly lower . Lowering the on target cool down per second via per auto-attack on that target (for a max of -3 seconds lower at all ranks) Would help make more use of his passive at all stages in the game.