Riot do you even play games to test the items, champions, ext before letting them go live?
Because apparently the people you allow on the PBE server to test this stuff are not very good at seeing something unbalanced. Let alone the dev team responsible for thinking up these redonkulous items.
Short and simple here we go: Guinsoo's Rageblade is way too good of an item right now. Remove the 8 stacks bonus damage and lifesteal and spell vamp passive and lower the bonus damage by atleast 50%, the attack speed is fine however.
Frankly I don't care for your dev teams feelings at this point. They are totally out of it and do not have a clue at this point at what is balanced and what is not. You made an item that only costs 2500 gold perform like an item that costs at least 3500 gold. Are you guys seriously this dumb or do you just not give a care about whatever you do to this game anymore? Its a pointless question because you guys are just brain dead. Take some lessons from Age of Empires dev team, sure they are not perfect but at least they make their game very balanced.