Lifesteal is way too strong for a stat.
It could be on Vayne, Yasuo any AD champion.
By building Warlord,
Any lifesteal item,
An Adc Lifesteal way too much with Runnan Hurricane,
is another item that buff lifesteal,
Don't forget the +8% increase healing masteries.
No wonder the Artillery champion are not played,
every single poke done to an yasuo or ADC are regained by auto attacking the nearby jungle camp.
Do not forget that Crit influence alot lifesteal.
Spellvamp at least is based on the cooldown of abilities. I think Grievous wounds needs a buff.

This was my build on Yasuo,
my Q tornadoe would 1 shot a minion waves late game criting for 1200, and healing me for 900.
http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/2229934914/204329123

Look the top highest damage dealers at champion.gg