Hmm, this is a tuffie so much is already done, hehe
Aside from Fixing Bugs & stuff, This would be my order of priority list...:
All those new properties on Weapons/armor Workin
As many as possible of OSI Mobs/NPC's included in the distro
The ability to edit Ore Veins (what they contain) in-game for those who /really/ wanna try for a super-OSI clone.
Some scripts that are out there to be tweaked/verified and then included in the Distro, Things like UOT's plant system comes to mind...
Any missing items
A system for putting "flags" or storing info on a player for Quests so that Playermobile don't need to be edited each time... Something like an Array/Hash Table that gets serialized with Interface like player.QuestAddInfo( QuestName, QuestFlag, QuestInfo), and player.QuestgetInfo(QuestName, questFlag)... SOmehting like that.
Putting in Quests.
The [decorate command decorating all of the world
And then, a fully spawned OSI-like world.