There's just so much that needs to be worked on.

The skill system is way too linear: Vertical growth (5-100) is fine and dandy but there needs to be options for horizontal growth.

They need to ditch the idea of skill caps for non-crafting professions: Instead of having it so that everyone is everything all the time like Darkfall, they should instead implement a system where you can choose which skills affect your character up to some kind of limit. I hate the idea of being penalized for wanting to try something different when there is no need to be penalized for it.

They need to add abilities to combat, crafting, and harvesting: I'll hold back on suggesting combat ideas until the combat revision is mentioned, but crafting and harvesting is nothing more than "click button recieve bacon." There should be more interaction for these skill lines.

They need to remove players' abilities to place safe zones: Allowing this has never made sense to me. Safe zones aren't bad, in-so-much as they are balanced properly with non-safe zones, but allowing players to choose where the safe zones go seems like a huge balance oversight.

They need to add reactive defense structrues, such as archer towers: I'm not saying building in safe zones should be completely ruled out, but the majority of player-owned buildings should be freely attackable and as such they would need to be defended when people are asleep, at work, or just not playing.

Weapons and armor need to be continuously balanced and rebalanced: This is regardless of any combat revision. Many things can "kill" a game, but balance is probably one of the biggest.

There needs to be more resource types and they should not be able to found everywhere: Scarcity drives conflict. Conflict drives need. Need drives gameplay.

There needs to be more PvE options: Yeah, yeah, quests are the devil and all that jazz. Bull. Poorly-designed and poorly-implemented quests are the devil. When I play an MMO I start to forget that humans have the ability to be innovative. Then I go play something else. Anyway, quests aren't the only thing that would provide PvE content; it just needs to be challenging and different.

Variety is the spice of life.