All the yellow keystones are bad because they are so delayed that they almost never come into effect
Press the attack: 3 basic attacks. Your target can be dead before this even happens if you have skills in your rotation (eg: master yi Q)
Lethal Tempo: 1.5 second delay. Same issue as above: target is dead before it can even activate. I find it usually only activates on my SECOND target. Meaning going in 1v5 lategame. No early game keystone presence.
Fleet Footwork: No delay, but does no damage.
And yet people are complaining about keystones being broken? They must be talking about the red ones then? Because my yellow keystones feel mostly useless (but I need them because the yellow tree is superior overall on my champ...)