I know it's been mentioned, but a casual search didn't bring it up, so I'm posting it again.
Shared exp. It really hurts to have exp solely defined by the killing blow. It pushes the player who gets the kill to more likely get future kills. This makes group combat against monsters an unsatisfying minigame played against your allies. Here's a side note: enemies which due to poison award no exp at all.
A suggestion is to provide exp per swing based on the amount of damage done to the target. The exp should be mediated by the monster's exp value, so that killing high health monsters isn't the best just because you get more hits. There could be an additional bonus for the final blow, but spread out among all the players that hit the target, split by contribution.
That takes care of kill exp, but what about shared crafting exp? How about a method that grants exp based in the contribution of materials? So, say I collect a bunch of wood. If my clan mate uses that wood to cook food, build a wall, or shale some wood, he'll get a chunk of exp for crafting it, but then the contributor of the pieces would get exp for the pieces. This may not be feasible, but I assume we want to avoid radiating exp like it does in Ark. And I k ow this can get squicky, keeping track of who harvested the resources in a stack of two hundred. That said, I can think of a few ways, so it's not an impossible task. And maybe this will spawn a different use.