In the mid game, you can add in units like Lux and Irelia if you find them to add in Dazzler and Divine. You should use whatever units in the meantime that you can, but these two additions will help the most.
Additional comp tips
Morgana can be a strong choice to add into the comp if you are able to fit her in possibly over Lux. While Lux provides good CC, Morgana provides good damage while also shredding the magic resist of enemies.