Idea: Turn Lethal Tempo into Tank Buster

Each basic attack against enemy champions grands 1 Tempo stack (2 for melee) up to 6 stacks. Each stack increases your attack speed and maximum attack speed by 5% to 14% up to maximum 30% to 84% based on your champion level. Reaching max stacks your basic attacks does 2% target enemy champion's max health as bonus true damage. Lasts 6 seconds after exiting combat with enemy champions

Skirmishers Unlike Assassins, Skirmishers aim to shred through any nearby enemy that approaches. Because Skirmishers lack high-end burst damage or reliable ways of closing in on high-priority targets, they are instead armed with situationally powerful defensive tools to survive in the fray, along with extreme sustained damage to cut down even the most durable targets.

So basically the Skirmisher's job is to shred enemy tanks. My suggestion would help any champion that is considered a tank buster and champions that rely on their basic attacks to deal with tanks. Tempo is not a burst keystone and may not do well vs squishier glass cannons but it would be great in situations that requires high dps over insta-burst

Some of the champions that be considered a tank shredders are Yi, Vayne

Vi for most of the part is used as a burst diver but she also have anti-tank ability Denting Blows: Every 3rd attack against the same target does bonus phys damage and shreds enemy's armor by percent and increases her Attack Speed

Olaf also have massive attack speed while his E does true damage to enemies and it's cooldown is reduced by basic attacks. Sometimes he even picks Bloodrazor as jungle item