Already In Game
1. Spirit Dart (ect.) and Mage Weapon Skills
2. Damage Over Time spells (DoT's) - How do I miss you.
3. Shell as a seperate entity.
4. Mob Passive Following Behavior - Maybe not to the extent they had it but a little bit of following is fun!

Going To Be Implemented (But has not been implemented yet or may never be.)
5. Reraise, even though it was never implemented, they were going to and should have stuck with it. Saying this game does not need Reraise is like saying that the game doesn't need a 2.0 or to be remade at all.