I feel like riot should experiment with creating items with tradeoffs.
Currently, items will always benefit you, meaning that when an item is good, there is no reason not to buy it. I feel that riot could make some items with downsides that would be very hard to abuse, even if they are very strong.
Ideas: Cursed blade: 3000 gold +75 ad Unique passive: you deal 30% increased dmg, but take 20% increased damage.
Non-violent chest-plate: 3200 gold 700 health 60 armor 40 magic resist: Unique passive: Your spells and attacks cannot deal over 100 damage under any circumstances
Assasins dagger: 3100 gold +80 ad +10% CDR Unique active: mark a target, after 1.5 seconds, both you and the target take damage equal to 125% of your bonus AD as physical damage.