1.) Crafting rework to give each craft its own unique and engaging gameplay. Some could well be turned into a minigame, but ideally, the old playstyle is preserved for one craft for the people who enjoy it as is. In addition, crafting leves should work like Ixal quests and provide you with the required materials.
2.) Healing rework to allow for a more healthy metagame - That means nerfs and a lot more interaction between skills to prevent one-button spamming gameplay. Ideally, a bad healer would need regular mana breaks, a decent healers could keep going without breaks if focusing on healing and an excellent healers could contribute some DPS as well. This one is a pipe dream however, as it would require not just the jobs, but also the content itself to be fundamentally re-designed.