Phoenix (like Reyna and Yoru) cannot use movement to create space as efficient as Jett, Neon or Raze. His kit is not movement based, therefore it needs to be buffed with space taking in mind. Heres my approach to this buff, let me know how you would buff Phoenix.
Wall - make it like Viper's... Still lasts the same, still damages the same but can go through the walls to instantly deny the vision of the opponents
Flash - 1,1second is so garbage, it needs to last at least 2 seconds, not to be pushed away from meta by flashing aggressive initiators (Skye and KAYO) just for that one reason
Molly - Make it so Phoenix can toss a molly from a bigger distance to have more safety when clearing angles (binded to the left click) and keep the way molly currently falls after a second (binded to the right click) & still recharges after 2 kills
Ultimate - make it last 2 or 3 more seconds, but increase the amount of orbs, kills or deaths it takes to charge it to 7