Keystone that unifies Lethal Tempo and Press the Attack

Each basic attack against same enemy champions grands 15-30% attack speed (based on level) which stacks up to 3 times for 3 seconds. Every 3rd attack against the same champion deals 18-180 bonus adaptive damage (based on level) and may be reapplied multiple times on same target. Those bonuses are lost when switching targets

The idea of this keystone is to combine Lethal Tempo and Press the Attack into 1 keystone. The keystone is for champions who rely heavily on their basic attacks. Attack speed will allow to apply damage from basic attacks more often while multiple applications of the damage every few attacks awards higher damage over time while focusing the same target without feeling of being bursted.

Lethal Tempo takes too long to stack for teamfight especially for melee champions that are exposed to direct damage from entire enemy team. Press the attack barely does any damage and the percent bonus damage after barely exists. So I think a keystone that is something in between will feel much better for all auto attack focused champions like Master Yi, Xin Zhao, Diana, Vayne, Udyr, Vayne, Varus, Tristana and nearly every auto attack focused champions. Those champions utilize well attack speed and bonus damage will greatly improve their sustain while focusing the same target. Also these champions have something in common - every X attacks you apply bonus damage so such keystone compliments this. Also saying exactly how much attack speed and how much damage exactly would be applied would be easier to balanced than 10-20% bonus damage applied from Press the Attack. The percent damage can be either too strong or too weak but flat damage will feel much better.

You take Fleet Footwork because you need extra sustain a some mobility, Conqueror is taken to deal with tanks and unified keystone as I suggested would be used against squishier opponents so the choices become much more clear. Currently it feels like both Lethal Tempo and Press the attack actually try to achieve the same goal but I think it will be much better if we just unify both keystones into something that benefits auto attack focused champion having both the extra damage every X attacks and bonus attack speed that they need which will greatly improve their sustain damage