Something reguarding Blue Kayn passive

So currently, I'm into blue Kayn, though regarding his passive, I have some minor concerns reguarding its clarity.

For those who have never seen blue Kayn (because all you see is Raast), basically Shadow Assassin's passive states that Kayn's damage is amplified by adding additional magic damage to the total damage you deal for 3 seconds (refreshed after you leave an enemy champion with your ultimate)

Seeing shadow assassin's passive is incredibly important when it comes to assassinations, especially when your behind because that damage amplification is litterally your only safety net to get back in the game + heavy reliance on ultimate to refresh the damage amplification (which is kinda why red kayn is much better than Blue Kayn, because its much easier to stay in the game with Red Kayn thanks to his constant sustain, while for blue is much harder, seeing getting on the enemy isn't quite as fast as someone like Zed, and you're just as squishy, you also need to rely on your ultimate more to refresh the passive, otherwise you do no damage.)

I feel there should be a more obvious indicator to when your passive is active, and inactive so you can more properly pace your DPS (asides from looking at your ability preview and seeing if your passive is on CD, or looking at your buffs bar)

Perhaps when shadow assassin's passive is available, Kayn's scythe begins to glow a blue smoke, signalling that your damage at this moment will be amplified for three seconds.

The scythe stops glowing after 3 seconds of using it, maybe making a "bong" noise or something showing that your passive has timed out.

Hopefully this'll make it easier to pace blue kayn's damage when doing burst and knowing when to refresh your passive with ultimate.

I doubt this'll bring blue kayn into the meta, I just feel like the passive is too important to just let the player just guess when his passive has timed out to cast ultimate

(not sure if blue Kayn needs actual buffs, because he already does good damage if you know how to make full use of the passive and duskblade, we'll have to see if red Kayn is still dominant if an assassin meta passes by, because if Red is still a thing in a meta where blue kayn should be dominating, then there should be for sure numbers changes, for now, I'm just concerned with clarity of passive)