Let me explain the build. Since lethality got nerved and Shaco's AP scaling got nerfed, Shaco went through a plunge in play rate. But these past few patches have been a blessing for Shaco. One, IE's price got reduced, making it a better early-mid game item, Statik Shiv got buffed(again) and most importantly, Ravenous Hydra got that 5AD buff, which absoluting changed everything about Shaco.

Yeah, the 5 ad buff was a joke, but i still prefer Rav over Titanic. If you do the math, Rav does more damage and the life steal will eventually heal you for more than what titanic gives in base health. Rae's active does 60-100% of your AD, which by late game will be 200-400 damage. If you got Titanic, the active would only do 300 tops since you're not building any other health items(maybe you will, but not with this build). "But wait, 300 is still greater than 200, Rav's minimum damage, plus Titanic has on hit damage." Yes, but Rav gives 80 AD, versus the lowly 35AD titanic gives. That means Titanic's on hit damage would be matched, crits will be stronger and your E does more damage, If you build ravenous that is.

Yeah, with GA now being a more effective item on ADC's, Shaco lost a means of getting free gold. Lethality is only effective when the enemy has a lower amount of armor(you can search up the math for calculating damage reduction on resistances). Basically, the more armor you build, the less is actually reduces damage. 50 armor reduces 33%, 100 reduces 50%, 150 reduces 60%, 200 reduces 66&. You see the pattern right? But that means if a target has more armor, the further away you get from that critical point where a small amount of armour reduced means an insane amount of extra damage.