The problem isn't lethality alone.
The real problem is stacking %shred with lethality making full ad teams actually viable, which is ridiculous. In what world should a team of 4ad outscale a team with 2 tanks? Back then if you drafted a full ad team you will get walled if the enemy had 2 or more tanks. Lethality is fine as it is. I suggest we tone down the bonus %penetration on the last whisper upgrades to 30%.
vest counters an entire builds worth of lethality