I would love it if Riot would add a 7th item slot just for consumble items.
The reasoning behind this is towards late game I always end up with a full inventory and large amounts of gold while i'm waiting to finish items. Anytime towards the end of the game, as I play carries, I always end upw itha full inventory and gold to spare for wards, but I can't buy them. It ends up falling to someone who has gotten less gold then me to buy the wards as they have slots available. This is also the crucial time for wards, as warding Baron, dragon, and the buffs can make a huge difference.
In conclusion, I suggest that Riot add in a seventh item slot purely for consumable items.