Riot should NOT buff AP itemization unless every single AP scaling champion is underperforming.
Just up and buffing AP items because people say that they are weak would throw away months of tuning on AP champions. Buffing AP would literally buff every single AP user, so if an AP champ is even a little overtuned, they would immediately become super strong.
Champions are balanced around the current itemization, which has been more-or-less solid since Mid-Season 6. Throwing every balance change made since then out the window because "AP feels weak" would NOT be good for the game.
Keep in mid that if any AP has been underperforming, Riot has buffed them by increasing their AP scaling. This is a much better approach to balancing AP than throwing caution to the wind and saying "let's buff literally everyone who uses AP".